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Even and odd functions

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51009711
Which function has a graph that is symmetric about the origin? a) \(y = x(4 - x^2)\) b) \(y = x(4 - x)\) c) \(y = (4 - x)(4 + x)\) d) \(y = x(4 - x)^2\)

Hints

- Recall the equation that defines an odd function. - Expand each expression and examine the powers of \(x\). - You can also compare the function values at \(x = 1\) and \(x = -1\).

Solution

1. A graph is symmetric about the origin when its function is odd, so \(f(-x) = -f(x)\). 2. For a), \(f(x) = x(4 - x^2) = 4x - x^3\). Both terms have odd powers, so \(f(-x) = -f(x)\). 3. For b), \(f(x) = 4x - x^2\), which contains both odd and even powers. 4. For c), \(f(x) = 16 - x^2\), which is even and is symmetric about the y-axis. 5. For d), \(f(x) = 16x - 8x^2 + x^3\), which contains both odd and even powers.

Answer

a) \(y = x(4 - x^2)\)
51011111
Which function has a graph that is symmetric about the y-axis? a) \(f(x)=x^3+1\) b) \(f(x)=(x^3-1)^2\) c) \(f(x)=(x^3+1)^2\) d) \(f(x)=(x^3-1)(x^3+1)\)

Hints

- Use the condition \(f(-x)=f(x)\). - Consider how even and odd powers change when \(x\) is replaced by \(-x\). - Expanding or using a special-product identity may reveal the powers more clearly.

Solution

1. A graph is symmetric about the y-axis when \(f(-x)=f(x)\). 2. For choice d), use the difference of squares: \(f(x)=x^6-1\). 3. Then \(f(-x)=(-x)^6-1=x^6-1=f(x)\), so choice d) is even. 4. The other choices contain a nonzero odd-power term after expansion, so they do not satisfy \(f(-x)=f(x)\).

Answer

d) \(f(x)=(x^3-1)(x^3+1)\)
51492011
Without calculating the solutions, determine how many real solutions each equation has. Justify each answer using the graph of the corresponding power function. a) \(x^6=10\) b) \(x^3=-8\) c) \(x^4=-5\) d) \(x^5=0\)

Hints

- An even power function is symmetric about the y-axis and has no negative outputs. - An odd power function takes every real output value exactly once. - Interpret each equation as an intersection with a horizontal line.

Solution

1. The graph of \(y=x^6\) is symmetric about the y-axis and has only nonnegative outputs. The horizontal line \(y=10\) intersects it twice, so there are two real solutions. 2. The graph of \(y=x^3\) is an odd function that increases through all real output values. The line \(y=-8\) intersects it once, so there is one real solution. 3. The graph of \(y=x^4\) has no negative outputs. The line \(y=-5\) does not intersect it, so there are no real solutions. 4. The graph of \(y=x^5\) intersects the line \(y=0\) only at the origin, so there is one real solution.

Answer

a) Two real solutions b) One real solution c) No real solutions d) One real solution
52182711
Determine algebraically whether each function is even, odd, or neither. a) \(f(x)=\frac{x^2-9}{x^2+1}\) b) \(g(x)=\frac{1}{2}x^3-2x\) c) \(h(x)=x^2(x-3)\)

Hints

- Replace \(x\) with \(-x\) in each rule. - Compare the result with the original function and its negative. - Expand the product in part c) if needed.

Solution

1. For \(f\), \(f(-x)=\frac{(-x)^2-9}{(-x)^2+1}=\frac{x^2-9}{x^2+1}=f(x)\). Therefore, \(f\) is even. 2. For \(g\), \(g(-x)=\frac{1}{2}(-x)^3-2(-x)=-\frac{1}{2}x^3+2x=-g(x)\). Therefore, \(g\) is odd. 3. Expand \(h(x)=x^3-3x^2\). Then \(h(-x)=-x^3-3x^2\), which is neither \(h(x)\) nor \(-h(x)\). Therefore, \(h\) is neither even nor odd.

Answer

a) Even; symmetric about the y-axis b) Odd; symmetric about the origin c) Neither even nor odd
52182911
For the polynomial family \(f_a(x)=x^4+(a^2-1)x^3+3x^2\), determine whether exactly one or more than one real value of \(a\) makes \(f_a\) even.

Hints

- Identify the term that prevents the polynomial from being even. - Set its coefficient equal to \(0\). - Solve the resulting quadratic equation completely.

Solution

1. An even polynomial can contain only even powers with nonzero coefficients. 2. Therefore, the coefficient of \(x^3\) must equal \(0\): \(a^2-1=0\). 3. Factoring gives \((a-1)(a+1)=0\), so \(a=1\) or \(a=-1\). 4. Thus, more than one real parameter value works.

Answer

There are two values: \(a=-1\) and \(a=1\).
52187511
Let \(f(x)=3x^4-5x^2+7\). 1) Use the powers in the rule to identify the graph’s symmetry. 2) A student wants to change only the constant term \(7\) so that the resulting function is odd. Determine whether this is possible and explain.

Hints

- Classify each exponent as even or odd. - Remember that a nonzero constant is an \(x^0\) term. - Decide whether changing one coefficient affects the other terms.

Solution

1. Every nonzero term has an even exponent, including the constant term with exponent \(0\). Therefore, \(f(-x)=f(x)\), so \(f\) is even. 2. An odd polynomial can contain only odd-power terms with nonzero coefficients. Changing the constant term can remove the \(x^0\) term by setting it to \(0\), but the terms \(3x^4\) and \(-5x^2\) remain. 3. Therefore, changing only the constant term cannot make the function odd.

Answer

1) The function is even and its graph is symmetric about the y-axis. 2) It is impossible. The even-power terms \(3x^4\) and \(-5x^2\) remain regardless of the constant term.
52188011
Let \(h(x)=x^5-4x^3+kx\), where \(k\in\mathbb{R}\). 1) Show algebraically that \(h\) is odd for every value of \(k\). 2) Explain why \(g(x)=h(x)+3\) is not odd.

Hints

- Replace \(x\) with \(-x\) in every term. - Compare the shifted function at \(-x\) with its negative. - Interpret adding \(3\) as a vertical translation.

Solution

1. Substitute \(-x\): \(h(-x)=(-x)^5-4(-x)^3+k(-x)=-x^5+4x^3-kx=-h(x)\). Thus, \(h\) is odd for every real \(k\). 2. For \(g\), \(g(-x)=-h(x)+3\), while \(-g(x)=-h(x)-3\). Since these expressions are not equal, \(g\) is not odd. 3. Geometrically, adding \(3\) shifts the graph upward, moving its center of symmetry from \((0, 0)\) to \((0, 3)\).

Answer

1) \(h(-x)=-h(x)\) for every \(k\), so \(h\) is odd. 2) \(g(-x)=-h(x)+3\ne-h(x)-3=-g(x)\), so \(g\) is not odd.
52200611
Consider \(g(x)=\frac{x^4-1}{(x-2)(x+5)}\). Use the domain to explain why the graph can be neither symmetric about the y-axis nor symmetric about the origin.

Hints

- Find the values that make the denominator \(0\). - Check whether every excluded value has its opposite excluded as well. - Both standard symmetries require a domain that is symmetric about \(0\).

Solution

1. The denominator is \(0\) at \(x=2\) and \(x=-5\), so the domain is \(\mathbb{R}\setminus\{-5, 2\}\). 2. Either y-axis symmetry or origin symmetry requires the domain to be symmetric about \(0\): whenever \(x\) is in the domain, \(-x\) must also be in the domain. 3. Here, \(5\) is in the domain but \(-5\) is not. Similarly, \(-2\) is in the domain but \(2\) is not. 4. Therefore, the domain fails a necessary condition for both symmetries.

Answer

The domain is \(\mathbb{R}\setminus\{-5, 2\}\), which is not symmetric about \(0\). Therefore, the graph has neither y-axis symmetry nor origin symmetry.
52316311
For each condition, give two different choices of exponents \(n\) and \(m\) from \(\{1, 2, 3, 4, 5, 6\}\) and a constant \(c \in \mathbb{R}\) so that \(f(x) = x^n + 5x^m + c\) satisfies the condition. a) The graph of \(f\) is symmetric about the y-axis. b) The graph of \(f\) is symmetric about the origin.

Hints

- Determine whether each symmetry condition requires even powers or odd powers. - Treat the constant \(c\) as the term \(cx^0\). - Decide whether a vertical shift is compatible with symmetry about the origin.

Solution

1. For symmetry about the y-axis, \(f\) must be even. Therefore, \(n\) and \(m\) must both be even. The constant \(c\) may be any real number. Two examples are \((n, m, c) = (2, 4, 3)\) and \((6, 2, 0)\). 2. For symmetry about the origin, \(f\) must be odd. Therefore, \(n\) and \(m\) must both be odd, and the constant term must be zero. Two examples are \((n, m, c) = (1, 3, 0)\) and \((5, 1, 0)\).

Answer

a) Sample answers: \((n, m, c) = (2, 4, 3)\) and \((6, 2, 0)\). In general, \(n, m \in \{2, 4, 6\}\) and \(c \in \mathbb{R}\). b) Sample answers: \((n, m, c) = (1, 3, 0)\) and \((5, 1, 0)\). In general, \(n, m \in \{1, 3, 5\}\) and \(c = 0\).
52317911
Determine algebraically whether the graph of \(f(x) = 3x^6 - 4x^2 + 7\) has y-axis symmetry, origin symmetry, or neither.

Hints

- Substitute \(-x\) for every occurrence of \(x\). - Simplify powers with even exponents. - Compare the result with \(f(x)\) and \(-f(x)\).

Solution

1. Substitute \(-x\) for \(x\): \(f(-x) = 3(-x)^6 - 4(-x)^2 + 7\). 2. Because the exponents \(6\) and \(2\) are even, \(f(-x) = 3x^6 - 4x^2 + 7\). 3. Therefore, \(f(-x) = f(x)\), so \(f\) is even and its graph is symmetric about the y-axis.

Answer

The graph is symmetric about the y-axis because \(f(-x) = f(x)\).
52328211
Determine algebraically whether each polynomial function is even or odd. 1. \(p(x) = 3x^5 - 2x^3 + x\) 2. \(q(x) = x^4 - 2x^2 + 5\)

Hints

- Substitute \(-x\) for every occurrence of \(x\). - Simplify one power at a time. - Compare the result with the original function. - If the result is not the original function, compare it with the opposite of the function.

Solution

1. \(p(-x) = 3(-x)^5 - 2(-x)^3 + (-x) = -3x^5 + 2x^3 - x = -p(x)\). Therefore, \(p\) is odd. 2. \(q(-x) = (-x)^4 - 2(-x)^2 + 5 = x^4 - 2x^2 + 5 = q(x)\). Therefore, \(q\) is even.

Answer

1. \(p\) is odd; its graph is symmetric about the origin. 2. \(q\) is even; its graph is symmetric about the y-axis.
52561711
Determine algebraically whether each function is even, odd, or neither. a) \(f(x)=\frac{e^x+e^{-x}}{2}\) b) \(g(x)=x^3\cos(x)\)

Hints

- Replace \(x\) with \(-x\) in each function. - Recall the symmetry identity for cosine. - Compare the result with both \(f(x)\) and \(-f(x)\).

Solution

1. For \(f\), substitute \(-x\): \(f(-x)=\frac{e^{-x}+e^x}{2}=f(x)\). Therefore, \(f\) is even, and its graph is symmetric about the y-axis. 2. For \(g\), \(g(-x)=(-x)^3\cos(-x)\). Since \((-x)^3=-x^3\) and \(\cos(-x)=\cos(x)\), \(g(-x)=-x^3\cos(x)=-g(x)\). Therefore, \(g\) is odd, and its graph has origin symmetry.

Answer

a) Even; the graph is symmetric about the y-axis. b) Odd; the graph has origin symmetry.
52561811
Determine algebraically whether each function is even, odd, or neither. a) \(h(x)=\frac{x^2-4}{x^3}\) b) \(k(x)=\sin(x^2)+x\)

Hints

- Test the equations \(f(-x)=f(x)\) and \(f(-x)=-f(x)\). - Simplify \((-x)^2\) and \((-x)^3\) carefully. - Compare the entire expression after substituting \(-x\).

Solution

1. For \(h\), \(h(-x)=\frac{(-x)^2-4}{(-x)^3}=\frac{x^2-4}{-x^3}=-h(x)\). Therefore, \(h\) is odd, and its graph has origin symmetry. 2. For \(k\), \(k(-x)=\sin((-x)^2)-x=\sin(x^2)-x\). This is neither \(k(x)=\sin(x^2)+x\) nor \(-k(x)=-\sin(x^2)-x\). Therefore, \(k\) is neither even nor odd.

Answer

a) Odd; the graph has origin symmetry. b) Neither even nor odd.
52750311
Determine whether \(f(x)=x^2\sqrt{x^2+5}\) is even, odd, or neither.

Hints

- Check the domain first. - Replace \(x\) with \(-x\). - Simplify the squared expressions before comparing.

Solution

1. Since \(x^2+5>0\) for every real \(x\), the domain is \(\mathbb{R}\), which is symmetric about \(0\). 2. Substitute \(-x\): \(f(-x)=(-x)^2\sqrt{(-x)^2+5}=x^2\sqrt{x^2+5}=f(x)\). 3. Therefore, \(f\) is even.

Answer

The function is even, so its graph is symmetric about the y-axis.
52828511
Complete the tables for the power functions \(f(x) = x^4\) and \(g(x) = x^7\). Use the symmetry of each graph. a) <table> <tr><td>\(x\)</td><td>\(f(x)\)</td></tr> <tr><td>\(0.8\)</td><td>\(0.4096\)</td></tr> <tr><td>\(1.5\)</td><td>\(5.0625\)</td></tr> <tr><td>\(-0.8\)</td><td></td></tr> <tr><td>\(-1.5\)</td><td></td></tr> </table> b) <table> <tr><td>\(x\)</td><td>\(g(x)\)</td></tr> <tr><td>\(0.6\)</td><td>\(0.0279936\)</td></tr> <tr><td>\(1.2\)</td><td>\(3.5831808\)</td></tr> <tr><td></td><td>\(-0.0279936\)</td></tr> <tr><td></td><td>\(-3.5831808\)</td></tr> </table>

Hints

- Use the exponent to decide whether each power function is even or odd. - Determine whether changing the sign of \(x\) changes the function value. - For an even function, \(f(-x) = f(x)\). - For an odd function, \(f(-x) = -f(x)\).

Solution

1. The function \(f(x) = x^4\) is even, so \(f(-x) = f(x)\). Therefore, \(f(-0.8) = 0.4096\) and \(f(-1.5) = 5.0625\). 2. The function \(g(x) = x^7\) is odd, so \(g(-x) = -g(x)\). 3. Since \(g(0.6) = 0.0279936\), the input that gives \(-0.0279936\) is \(-0.6\). 4. Since \(g(1.2) = 3.5831808\), the input that gives \(-3.5831808\) is \(-1.2\).

Answer

a) \(f(-0.8) = 0.4096\) and \(f(-1.5) = 5.0625\) b) The missing inputs are \(-0.6\) and \(-1.2\), in that order.
52906111
Let \(f(x)=(x+5)^4-2(x+5)^2\). Show algebraically that the graph is symmetric about the vertical line \(x=-5\).

Hints

- Use inputs equally far from the proposed vertical axis. - Substitute \(-5+h\) and \(-5-h\). - Simplify the even powers of \(h\).

Solution

1. Symmetry about \(x=-5\) requires \(f(-5+h)=f(-5-h)\) for every real \(h\). 2. \(f(-5+h)=h^4-2h^2\). 3. \(f(-5-h)=(-h)^4-2(-h)^2=h^4-2h^2\). 4. Therefore, \(f(-5+h)=f(-5-h)\) for every real \(h\), proving symmetry about \(x=-5\).

Answer

Both \(f(-5+h)\) and \(f(-5-h)\) simplify to \(h^4-2h^2\). Therefore, the graph is symmetric about \(x=-5\).
53246111
Match each function to graph a, b, or c. Justify your matches using symmetry and a key point such as the y-intercept. \(f(x)=\frac{4x}{x^2+2}\) \(g(x)=\cos(0.5x)-1\) \(h(x)=\frac{4}{x^2+2}\)
Figure for problem 532461

Hints

- Test each rule for even or odd symmetry. - Use the y-intercept to distinguish the two even functions. - Match each algebraic feature to the graph.

Solution

1. For \(f\), \(f(-x)=-f(x)\), so its graph is symmetric about the origin. Only graph c has this symmetry, so \(f\) matches graph c. 2. For \(g\), \(g(-x)=g(x)\), so it is even. Also, \(g(0)=\cos(0)-1=0\). The even graph through the origin is graph a. 3. For \(h\), \(h(-x)=h(x)\), so it is even. Its y-intercept is \(h(0)=2\), identifying graph b.

Answer

Graph a: \(g(x)=\cos(0.5x)-1\) Graph b: \(h(x)=\frac{4}{x^2+2}\) Graph c: \(f(x)=\frac{4x}{x^2+2}\)
53347711
Let \(f(x)=x^3\). a) Solve \(f(x)=-8\). b) How many intersection points does the graph of \(f\) have with the line \(y=5\)? Explain using the graph’s behavior, and state how odd symmetry relates this intersection to the one with \(y=-5\). c) Give an example of a power function \(g(x)=ax^3\) whose graph is vertically compressed compared with \(f\). Is your example even, odd, or neither?
Figure for problem 533477

Hints

- Identify the number whose cube is \(-8\). - Consider how many times a horizontal line can cross a strictly increasing cubic graph, and recall that an odd graph has origin symmetry. - A vertical compression uses a coefficient whose absolute value is between \(0\) and \(1\); test \(g(-x)\) to classify the symmetry.

Solution

1. Solve \(x^3=-8\): \(x=\sqrt[3]{-8}=-2\). 2. The function \(f(x)=x^3\) is strictly increasing and takes every real output value exactly once, so the line \(y=5\) intersects the graph once. Also, \(f(-x)=-f(x)\), so the graph is odd: if \((r, 5)\) is the intersection with \(y=5\), then \((-r, -5)\) is the corresponding intersection with \(y=-5\). 3. A vertical compression occurs when \(0<|a|<1\). One example is \(g(x)=0.5x^3\). Since \(g(-x)=-g(x)\), this function is also odd.

Answer

a) \(x=-2\) b) One intersection point. Odd symmetry gives a corresponding intersection with \(y=-5\) at the opposite x-coordinate. c) Sample answer: \(g(x)=0.5x^3\), which is odd.
53349111
Describe the domain, range, and symmetry of \(f(x)=x^3\) and \(g(x)=x^6\). Use the graph as a visual reference.
Figure for problem 533491

Hints

- Check whether either function has restrictions on its input. - Determine whether each function can produce negative outputs. - Compare \(f(-x)\) with \(f(x)\), and do the same for \(g\).

Solution

1. Both functions are defined for every real input, so both domains are \((-\infty, \infty)\). 2. The cubic function takes every real value, so the range of \(f\) is \((-\infty, \infty)\). The sixth-power function is never negative, so the range of \(g\) is \([0, \infty)\). 3. Since \(f(-x)=-f(x)\), \(f\) is odd and its graph is symmetric about the origin. Since \(g(-x)=g(x)\), \(g\) is even and its graph is symmetric about the y-axis.

Answer

For \(f(x)=x^3\): domain \((-\infty, \infty)\), range \((-\infty, \infty)\), symmetric about the origin For \(g(x)=x^6\): domain \((-\infty, \infty)\), range \([0, \infty)\), symmetric about the y-axis
53349611
Match graphs \(f\), \(g\), and \(h\) to the correct function rules. 1. \(y=x^2\) 2. \(y=x^3\) 3. \(y=\frac{1}{x}\) Justify the matches using symmetry and other visible graph features.
Figure for problem 533496

Hints

- Compare y-axis symmetry with origin symmetry. - Check whether each graph passes through the origin. - Identify the graph that approaches the coordinate axes as asymptotes.

Solution

1. Graph \(g\) is symmetric about the y-axis and has only nonnegative outputs, so it represents \(y=x^2\). 2. Graph \(h\) passes through the origin and is symmetric about the origin, with branches in Quadrants I and III. It represents \(y=x^3\). 3. Graph \(f\) has two separate branches in Quadrants I and III and approaches both coordinate axes without touching them. It represents \(y=\frac{1}{x}\).

Answer

\(f: y=\frac{1}{x}\); \(g: y=x^2\); \(h: y=x^3\)
53360311
A power function \(f(x)=ax^n\), where \(n\) is a positive integer, passes through \(A(2, 16)\) and \(B(-2, 16)\). a) Explain why \(n\) must be even. b) Find the function rule when \(n\) is the smallest possible positive integer satisfying this condition.
Figure for problem 533603

Hints

- Compare the outputs at opposite inputs. - Which parity of exponent gives y-axis symmetry? - Use the smallest positive even exponent, then substitute one point to find \(a\).

Solution

1. The opposite inputs \(2\) and \(-2\) give the same output. This is consistent with y-axis symmetry, so the exponent \(n\) must be even. 2. The smallest positive even integer is \(n=2\). 3. Substitute \((2, 16)\) into \(f(x)=ax^2\): \(16=a(2^2)=4a\), so \(a=4\). 4. Therefore, \(f(x)=4x^2\).

Answer

a) Since \(f(2)=f(-2)\), the function has y-axis symmetry, which requires an even exponent. b) \(f(x)=4x^2\)
53361911
Let \(f(x)=x^3\) and \(g(x)=-x^3\). a) Describe a geometric reflection that maps the graph of \(f\) onto the graph of \(g\). b) In which quadrants does the graph of \(g\) lie?
Figure for problem 533619

Hints

- A negative sign outside a function negates every output. - Test one positive and one negative input. - Relate the result to the origin symmetry of an odd function.

Solution

1. Since \(g(x)=-f(x)\), every output of \(f\) is multiplied by \(-1\). This reflects the graph across the x-axis. Because \(f\) is odd, reflection across the y-axis produces the same graph. 2. For \(x<0\), \(g(x)>0\), so the graph lies in Quadrant II. For \(x>0\), \(g(x)<0\), so it lies in Quadrant IV. It also passes through the origin.

Answer

a) Reflect the graph of \(f\) across the x-axis. Reflection across the y-axis also gives the same graph. b) The graph lies in Quadrants II and IV and passes through the origin.
53364411
The figure shows graphs a, b, and c. Match each graph to one function, and justify your choices using symmetry. - \(f(x) = 0.1x^4 - 2x^2 + 3\) - \(g(x) = 0.2x^3 - 4x\) - \(h(x) = 0.2x^3 - x^2 + 2\)
Figure for problem 533644

Hints

- Identify which function contains only even powers. - Identify which function contains only odd powers. - Compare those algebraic symmetry types with the visible graph symmetries.

Solution

1. The function \(f\) contains only even powers of \(x\), so it is even. Its graph is symmetric about the y-axis, which matches graph a. 2. The function \(g\) contains only odd powers of \(x\), so it is odd. Its graph is symmetric about the origin, which matches graph b. 3. The function \(h\) contains both even and odd powers, so it is neither even nor odd. Its graph has neither y-axis symmetry nor origin symmetry, which matches graph c.

Answer

\(a \to f\), \(b \to g\), and \(c \to h\)
53403211
The diagram shows graphs p, q, and r. Match each graph to one function. Use symmetry and behavior as \(x\to\infty\). \(a(x)=\frac{2x}{x^2+1}\) \(b(x)=\cos(x)\) \(c(x)=e^{-0.2x^2}\)
Figure for problem 534032

Hints

- Identify the odd function first. - Distinguish the even functions by periodicity and end behavior. - Check what each function approaches for large positive \(x\).

Solution

1. Since \(a(-x)=-a(x)\), \(a\) is odd. The only graph symmetric about the origin is p, so p represents \(a\). 2. Both \(b\) and \(c\) are even. The cosine function oscillates between \(-1\) and \(1\), so the periodic graph q represents \(b\). 3. For \(c\), the exponent \(-0.2x^2\to-\infty\), so \(c(x)\to0\). The even graph that approaches the x-axis is r.

Answer

Graph p: \(a(x)=\frac{2x}{x^2+1}\) Graph q: \(b(x)=\cos(x)\) Graph r: \(c(x)=e^{-0.2x^2}\)
51287611
Consider \(h(x) = 0.1x^4 - 1.6x^2\). a) Determine algebraically what symmetry the graph has. b) Find all x-intercepts and the y-intercept. c) Confirm the zeros algebraically by using the factored form \(0.1x^2(x^2 - 16)\).

Hints

- Compare \(h(-x)\) with \(h(x)\). - Use the zero-product property on the factored expression. - Convert each zero into its corresponding x-intercept.

Solution

1. The graph is symmetric about the y-axis. Algebraically, \(h(-x) = 0.1(-x)^4 - 1.6(-x)^2 = 0.1x^4 - 1.6x^2 = h(x)\), so \(h\) is even. 2. The y-intercept is \((0, 0)\). The x-intercepts occur where \(h(x) = 0\). 3. To find and confirm the zeros, solve \(0.1x^2(x^2 - 16) = 0\). 4. The zero-product property gives \(x^2 = 0\) or \(x^2 - 16 = 0\). Therefore, \(x = 0\), \(x = -4\), or \(x = 4\), so the x-intercepts are \((-4, 0)\), \((0, 0)\), and \((4, 0)\).

Answer

a) The graph is symmetric about the y-axis. b) The x-intercepts are \((-4, 0)\), \((0, 0)\), and \((4, 0)\). The y-intercept is \((0, 0)\). c) Solving \(0.1x^2(x^2 - 16) = 0\) confirms the zeros \(x = -4\), \(x = 0\), and \(x = 4\).
51488711
A power function has the form \(f(x) = ax^n\). Its graph passes through \(P(1, -2)\) and \(Q(2, -32)\). Find the function rule. Then determine whether the graph is symmetric about the y-axis or symmetric about the origin. Justify your answer using the exponent.

Hints

- Substitute the first point into the general form to find \(a\). - Use the second point and the value of \(a\) to determine \(n\). - How does an even or odd exponent affect a function's symmetry?

Solution

1. Substitute \(P(1, -2)\): \(-2 = a(1)^n\), so \(a = -2\). 2. Substitute \(Q(2, -32)\): \(-32 = -2(2^n)\). 3. Divide by \(-2\): \(16 = 2^n\), so \(n = 4\). Therefore, \(f(x) = -2x^4\). 4. Because \(n=4\) is even, \(f(-x)=f(x)\). The graph is symmetric about the y-axis.

Answer

\(f(x) = -2x^4\). Because the exponent \(4\) is even, the graph is symmetric about the y-axis.
51488811
A student claims that there is a power function \(f(x) = ax^n\), where \(n\) is a positive integer, with all three properties below: 1. The graph is symmetric about the origin. 2. The graph passes through \(P(2, 8)\). 3. The function is strictly decreasing over its entire domain. Determine mathematically whether such a function can exist. Justify your conclusion.

Hints

- What does symmetry about the origin tell you about \(n\)? - What does the point \((2, 8)\) tell you about the sign of \(a\)? - How do the sign of \(a\) and the parity of \(n\) affect whether the function increases or decreases?

Solution

1. Symmetry about the origin requires \(n\) to be odd. 2. Since the graph passes through \((2, 8)\), \(a \cdot 2^n = 8\), so \(a = \frac{8}{2^n} > 0\). 3. A power function \(f(x)=ax^n\) with odd positive integer \(n\) and \(a>0\) is strictly increasing over all real numbers. 4. This contradicts the requirement that the function be strictly decreasing. Therefore, no such function exists.

Answer

No such function exists. Origin symmetry requires an odd exponent, and the point \((2, 8)\) forces \(a>0\). That combination produces a strictly increasing function, not a decreasing one.
51491511
The graph of a power function \(g(x)=ax^n\) passes through \(Q(2, -16)\). a) Find \(a\) if \(n=4\). b) Find \(a\) if \(n=3\). c) One of the graphs from part a or part b also passes through \(R(-2, 16)\). Determine which one and justify your answer.

Hints

- Substitute the coordinates of the given point into \(g(x)=ax^n\). - Compare the symmetry of functions with even and odd exponents. - What happens to the sign of a negative base when it is raised to an even or odd power?

Solution

1. If \(n=4\), then \(-16=a(2^4)=16a\), so \(a=-1\). 2. If \(n=3\), then \(-16=a(2^3)=8a\), so \(a=-2\). 3. For part a, \(g(-2)=-1(-2)^4=-16\), so that graph does not pass through \(R\). 4. For part b, \(g(-2)=-2(-2)^3=16\), so \(g(x)=-2x^3\) passes through \(R\). This agrees with the origin symmetry of an odd power function.

Answer

a) \(a=-1\) b) \(a=-2\) c) The graph from part b, \(g(x)=-2x^3\), because \(g(-2)=16\).
51492111
Consider the equation \(x^n=c\). a) When \(n=4\), state the values of \(c\) for which the equation has no real solution, exactly one real solution, or exactly two real solutions. b) When \(n=7\), explain how many real solutions the equation has when \(c\) is positive, negative, or zero.

Hints

- Compare the graphs of \(y=x^4\) and \(y=x^7\). - Imagine moving the horizontal line \(y=c\) up and down. - Consider whether an even power can have a negative output.

Solution

1. For \(n=4\), the graph of \(y=x^4\) has range \([0, \infty)\). If \(c<0\), the horizontal line \(y=c\) does not intersect the graph. If \(c=0\), it intersects once at the origin. If \(c>0\), it intersects twice. 2. For \(n=7\), the graph of \(y=x^7\) is an odd function that increases through every real output value. Therefore, every horizontal line \(y=c\) intersects it exactly once, whether \(c\) is positive, negative, or zero.

Answer

a) No real solution when \(c<0\); exactly one real solution when \(c=0\); exactly two real solutions when \(c>0\) b) Exactly one real solution for every real value of \(c\)
51492211
A student makes this claim: “For an equation of the form \(x^n=c\), changing the sign of \(c\) always changes the number of real solutions.” Determine whether the claim is true. Consider two cases: Case 1: \(n\) is even, such as \(n=2\). Case 2: \(n\) is odd, such as \(n=3\). Support your conclusion with examples and the shapes of the graphs.

Hints

- Test the claim with simple values such as \(c=1\) and \(c=-1\). - Compare the ranges of an even power function and an odd power function. - A counterexample is enough to show that an “always” claim is false.

Solution

1. For an even exponent, compare \(x^2=4\) and \(x^2=-4\). The first equation has two real solutions, while the second has none. In this example, changing the sign changes the number of real solutions. 2. For an odd exponent, compare \(x^3=8\) and \(x^3=-8\). Each equation has exactly one real solution. Changing the sign changes the solution from \(2\) to \(-2\), but not the number of solutions. 3. Graphically, an even power function has no negative outputs, while an odd power function takes every real output value exactly once. Therefore, the claim is false in general.

Answer

The claim is false. For even exponents, changing a nonzero \(c\) from positive to negative changes the number of real solutions from two to zero. For odd exponents, both \(x^n=c\) and \(x^n=-c\) have exactly one real solution.
51543111
The graph of \(f(x)=kx^n\), where \(n\) is a positive integer, passes through \(P(-2, 4)\). a) Find \(k\) when \(n=2\) and when \(n=3\). b) Determine the sign of \(k\) in general. What sign must \(k\) have when \(n\) is even? What sign must it have when \(n\) is odd? Justify your answer using the coordinates of \(P\).

Hints

- Substitute the point into \(f(x)=kx^n\) and solve for \(k\). - Determine the sign of a negative number raised to an even or odd power. - What sign must \(k\) have so that the product equals a positive output?

Solution

1. For \(n=2\), substitute \((-2, 4)\): \(4=k(-2)^2=4k\), so \(k=1\). 2. For \(n=3\), \(4=k(-2)^3=-8k\), so \(k=-\frac{1}{2}\). 3. If \(n\) is even, \((-2)^n>0\). Since the output is \(4>0\), \(k\) must be positive. 4. If \(n\) is odd, \((-2)^n<0\). To make the product equal \(4>0\), \(k\) must be negative.

Answer

a) When \(n=2\), \(k=1\). When \(n=3\), \(k=-\frac{1}{2}\). b) If \(n\) is even, \(k>0\). If \(n\) is odd, \(k<0\).
52181711
Consider the functions \(f(x)=0.25x^4-2x^2+1\), \(g(x)=x^3+2\), and \(h(x)=-x^3+2\). a) Show algebraically that the graph of \(f\) is symmetric about the y-axis. b) Show that the graphs of \(g\) and \(h\) are reflections of each other across the y-axis. c) Explain why the graph of \(g\) itself is not symmetric about the y-axis.

Hints

- Replace every \(x\) with \(-x\). - Distinguish the condition for one graph to be symmetric from the condition for two graphs to be reflections of each other. - Compare \(g(-x)\) with both \(g(x)\) and \(h(x)\).

Solution

1. Replace \(x\) with \(-x\): \(f(-x)=0.25(-x)^4-2(-x)^2+1=0.25x^4-2x^2+1=f(x)\). Therefore, \(f\) is even and its graph is symmetric about the y-axis. 2. Compute \(g(-x)=(-x)^3+2=-x^3+2=h(x)\). Thus, reflecting the graph of \(g\) across the y-axis produces the graph of \(h\). 3. For \(g\) to be symmetric about the y-axis, it would need to satisfy \(g(-x)=g(x)\). Instead, \(-x^3+2\ne x^3+2\) for nonzero \(x\), so \(g\) is not even.

Answer

a) \(f(-x)=f(x)\), so \(f\) is symmetric about the y-axis. b) \(g(-x)=h(x)\), so the graphs of \(g\) and \(h\) are reflections across the y-axis. c) \(g(-x)\ne g(x)\) for nonzero \(x\), so \(g\) is not symmetric about the y-axis.
52181911
Determine whether each function is even, odd, or neither. a) \(f(x)=x(x-2)(x+2)\) b) \(g(x)=(x^2-9)(x^2+1)\) c) \(h(x)=(x-1)^2(x+1)\)

Hints

- Test whether \(p(-x)=p(x)\) or \(p(-x)=-p(x)\). - Simplifying the products may make the powers easier to inspect. - One counterexample is enough to rule out a proposed identity.

Solution

1. For \(f\), simplify to \(f(x)=x(x^2-4)=x^3-4x\). Then \(f(-x)=-x^3+4x=-f(x)\), so \(f\) is odd. 2. For \(g\), \(g(-x)=((-x)^2-9)((-x)^2+1)=(x^2-9)(x^2+1)=g(x)\), so \(g\) is even. 3. For \(h\), neither identity holds. For example, \(h(2)=3\) and \(h(-2)=-9\), so \(h(-2)\ne h(2)\) and \(h(-2)\ne-h(2)\). Therefore, \(h\) is neither even nor odd.

Answer

a) Odd; symmetric about the origin b) Even; symmetric about the y-axis c) Neither even nor odd
52182211
Let \(g(x)=ax+\frac{b}{x}\), with domain \(\mathbb{R}\setminus\{0\}\), where \(a\ne0\) and \(b\ne0\). 1) Show algebraically that \(g(-x)=-g(x)\) for all allowed values of \(a\) and \(b\). 2) Interpret \(g(-x)=-g(x)\) geometrically. 3) Find \(a\) and \(b\) so that the graph passes through \(P(1, 5)\) and \(Q(2, 8.5)\).

Hints

- Replace every \(x\) with \(-x\) and factor out \(-1\). - Connect the identity \(g(-x)=-g(x)\) with odd functions. - Substitute each point to create a system of two equations.

Solution

1. Substitute \(-x\): \(g(-x)=a(-x)+\frac{b}{-x}=-ax-\frac{b}{x}=-\left(ax+\frac{b}{x}\right)=-g(x)\). 2. Therefore, \(g\) is odd, so its graph is symmetric about the origin. 3. The point \(P(1, 5)\) gives \(a+b=5\). The point \(Q(2, 8.5)\) gives \(2a+\frac{b}{2}=8.5\), or \(4a+b=17\). Subtracting the first equation gives \(3a=12\), so \(a=4\). Then \(b=1\).

Answer

1) \(g(-x)=-g(x)\) 2) The graph is symmetric about the origin. 3) \(a=4\) and \(b=1\)
52182311
Classify each function as even, odd, or neither. Each function has a letter. Rearrange the five letters in each category to form an English word from nature. - \(f(x)=2x^4-x^2+3\) (M) - \(f(x)=x^5-2x\) (M) - \(f(x)=\frac{2}{x}\) (O) - \(f(x)=x^2+x\) (B) - \(f(x)=x^6+1\) (A) - \(f(x)=4x^3\) (U) - \(f(x)=x^4+x^3\) (I) - \(f(x)=x^{10}-5\) (P) - \(f(x)=x^7+x^5\) (S) - \(f(x)=(x+3)^2\) (R) - \(f(x)=7x^2\) (L) - \(f(x)=x^9\) (E) - \(f(x)=1-x^2\) (E) - \(f(x)=x-5\) (C) - \(f(x)=x^3-x+2\) (H)

Hints

- For polynomials, inspect whether the nonzero terms use only even powers or only odd powers. - Test the rational function by replacing \(x\) with \(-x\). - Expand shifted expressions before classifying them.

Solution

1. Even functions contain only even powers after simplification and satisfy \(f(-x)=f(x)\). The even entries are \(2x^4-x^2+3\) (M), \(x^6+1\) (A), \(x^{10}-5\) (P), \(7x^2\) (L), and \(1-x^2\) (E). Their letters form MAPLE. 2. Odd functions contain only odd powers and no nonzero constant term, and they satisfy \(f(-x)=-f(x)\). The odd entries are \(x^5-2x\) (M), \(\frac{2}{x}\) (O), \(4x^3\) (U), \(x^7+x^5\) (S), and \(x^9\) (E). Their letters form MOUSE. 3. The remaining functions have neither symmetry: \(x^2+x\) (B), \(x^4+x^3\) (I), \((x+3)^2\) (R), \(x-5\) (C), and \(x^3-x+2\) (H). Their letters form BIRCH.

Answer

Even: MAPLE Odd: MOUSE Neither: BIRCH
52182411
Let \(f\) be an even function, so \(f(-x)=f(x)\), and let \(g\) be an odd function, so \(g(-x)=-g(x)\). Determine whether \(h(x)=f(x)g(x)\) is even, odd, or neither. Prove your conclusion from the definitions. Then determine the symmetry of \(k(x)=g_1(x)g_2(x)\) when both \(g_1\) and \(g_2\) are odd.

Hints

- Substitute \(-x\) into each product. - Replace each factor using its even or odd identity. - Track the signs when multiplying two negative factors.

Solution

1. For \(h\), \(h(-x)=f(-x)g(-x)=f(x)(-g(x))=-f(x)g(x)=-h(x)\). Therefore, \(h\) is odd. 2. For \(k\), \(k(-x)=g_1(-x)g_2(-x)=(-g_1(x))(-g_2(x))=g_1(x)g_2(x)=k(x)\). Therefore, \(k\) is even.

Answer

\(h\) is odd and symmetric about the origin. \(k\) is even and symmetric about the y-axis.
52182511
Investigate these consequences of even and odd function symmetry. a) A function \(f\) is defined at \(x=0\) and is odd. Explain algebraically why \(f(0)=0\). b) A function \(g\) satisfies \(g(-3)=4\) and \(g(3)=4\). Explain why \(g\) cannot be odd. c) Show that a function that is both even and odd must be the zero function on its domain.

Hints

- Substitute a strategic value into the odd-function identity. - Compare the values at opposite inputs. - Combine the equations for even and odd functions.

Solution

1. Since \(f\) is odd, \(f(-x)=-f(x)\). At \(x=0\), this gives \(f(0)=-f(0)\), so \(2f(0)=0\) and \(f(0)=0\). 2. If \(g\) were odd, \(g(-3)=-g(3)\). The given values would require \(4=-4\), which is impossible. 3. If \(f\) is both even and odd, then \(f(-x)=f(x)\) and \(f(-x)=-f(x)\). Thus, \(f(x)=-f(x)\), so \(2f(x)=0\) and \(f(x)=0\) for every \(x\) in the domain.

Answer

a) \(f(0)=-f(0)\), so \(f(0)=0\). b) Odd symmetry would require \(g(-3)=-g(3)\), but the given values are both \(4\). c) The two identities imply \(f(x)=-f(x)\), so \(f(x)=0\) for every \(x\) in the domain.
52182611
Analyze how translations affect symmetry. a) Suppose \(f\) is even. Use an example, such as a parabola, to show that \(h(x)=f(x-c)\) with \(c\ne0\) is not generally symmetric about the y-axis. b) Suppose \(g\) is odd. Determine algebraically whether \(k(x)=g(x)+d\), where \(d\ne0\), remains symmetric about the origin.

Hints

- Test a simple translated parabola at opposite x-values. - Apply the odd-function identity to \(g(-x)\). - Compare \(k(-x)\) with \(-k(x)\).

Solution

1. Choose \(f(x)=x^2\) and \(c=1\). Then \(h(x)=(x-1)^2\). Since \(h(1)=0\) but \(h(-1)=4\), \(h(-x)=h(x)\) does not hold in general. The translation moves the symmetry axis from \(x=0\) to \(x=1\). 2. Since \(g\) is odd, \(k(-x)=g(-x)+d=-g(x)+d\). However, \(-k(x)=-g(x)-d\). These expressions are equal only when \(d=0\), so for \(d\ne0\), \(k\) is not symmetric about the origin.

Answer

a) For example, \(f(x)=x^2\) is even, but \(h(x)=(x-1)^2\) is not even because \(h(1)=0\ne4=h(-1)\). b) No. For \(d\ne0\), \(k(-x)=-g(x)+d\ne-g(x)-d=-k(x)\).
52182811
Determine the symmetry of each function and justify your answer. a) \(p(x)=\cos(x)+x^2\) b) \(q(x)=\frac{\sin(x)}{x^3}\), for \(x\ne0\) c) Let \(f_a(x)=x^3+(a+1)x^2-ax\). Find the real value of \(a\) for which \(f_a\) is odd.

Hints

- Recall whether sine and cosine are even or odd. - Track the signs in the numerator and denominator of the quotient. - For an odd polynomial, every nonzero term must have an odd exponent.

Solution

1. Since \(\cos(-x)=\cos(x)\) and \((-x)^2=x^2\), \(p(-x)=p(x)\). Thus, \(p\) is even. 2. Since \(\sin(-x)=-\sin(x)\) and \((-x)^3=-x^3\), \(q(-x)=\frac{-\sin(x)}{-x^3}=q(x)\). The domain is symmetric about \(0\), so \(q\) is even. 3. For \(f_a\) to be odd, its even-power term must vanish. Thus, \(a+1=0\), so \(a=-1\). Then \(f_{-1}(x)=x^3+x\), which is odd.

Answer

a) Even; symmetric about the y-axis b) Even; symmetric about the y-axis c) \(a=-1\)
52183011
For the rational-function family \(g_k(x)=\frac{x^2+4}{x-k+5}\), determine whether exactly one or more than one real value of \(k\) makes \(g_k\) odd.

Hints

- Use the identity \(g_k(-x)=-g_k(x)\). - The numerator is already even; determine when the denominator is odd. - Check that the resulting domain is symmetric about \(0\).

Solution

1. The numerator \(x^2+4\) is even. For the quotient to be odd, the linear denominator must be odd. 2. Rewrite the denominator as \(x+(5-k)\). A linear function of this form is odd only when its constant term is \(0\). 3. Set \(5-k=0\), which gives \(k=5\). 4. Verification: \(g_5(x)=\frac{x^2+4}{x}=x+\frac{4}{x}\), with domain \(x\ne0\). Both terms are odd, so \(g_5(-x)=-g_5(x)\). 5. Therefore, exactly one value of \(k\) works.

Answer

Exactly one value works: \(k=5\).
52183611
Find the rule of a cubic polynomial \(g\) with all three properties: 1) Its graph is symmetric about the origin. 2) It has a zero at \(x=2\). 3) It passes through \((1, 6)\).

Hints

- Use only odd powers in the general cubic form. - Translate the zero and the point into equations. - Solve the resulting system for the coefficients.

Solution

1. An odd cubic polynomial has the form \(g(x)=ax^3+bx\). 2. The zero at \(x=2\) gives \(8a+2b=0\), or \(4a+b=0\). 3. The point \((1, 6)\) gives \(a+b=6\). 4. Subtracting the second equation from the first relation gives \(3a=-6\), so \(a=-2\). Then \(b=8\). 5. Therefore, \(g(x)=-2x^3+8x\).

Answer

\(g(x)=-2x^3+8x\)
52183711
Let \(f(x)=x^3+(a+2)x^2+bx\), where \(a\) and \(b\) are real. Determine all ordered pairs \((a, b)\) for which \(f\) is odd. Also determine whether any ordered pair makes \(f\) even.

Hints

- Identify the even-power and odd-power terms. - An odd polynomial cannot have a nonzero even-power term. - An even polynomial cannot have a nonzero cubic term.

Solution

1. For \(f\) to be odd, the coefficient of its even-power term must be \(0\). Thus, \(a+2=0\), so \(a=-2\). 2. The coefficient \(b\) multiplies the odd-power term \(x\), so it may be any real number. Therefore, all pairs \((-2, b)\), where \(b\in\mathbb{R}\), make \(f\) odd. 3. For \(f\) to be even, every odd-power coefficient would need to be \(0\). The coefficient of \(x^3\) is fixed at \(1\), so no values of \(a\) and \(b\) can make \(f\) even.

Answer

Odd: all pairs \((-2, b)\) with \(b\in\mathbb{R}\) Even: no ordered pairs
52183911
Let \(f\) be an even polynomial. 1) Explain why every nonzero zero \(x_0\) must have a matching zero at \(-x_0\). 2) Suppose \(f\) has exactly three distinct real zeros. Identify one zero that \(f\) must have and justify your answer. 3) Give one possible rule for an even polynomial with exactly three distinct real zeros.

Hints

- Apply \(f(-x)=f(x)\) at a zero. - Count nonzero zeros in opposite pairs. - Build an even polynomial from factors for \(-1\), \(0\), and \(1\).

Solution

1. Since \(f\) is even, \(f(-x)=f(x)\). If \(f(x_0)=0\), then \(f(-x_0)=f(x_0)=0\), so nonzero zeros occur in opposite pairs. 2. Three is odd, while the nonzero zeros occur in pairs. Therefore, the unpaired zero must be \(x=0\), which is its own opposite. 3. Choose the distinct zeros \(-1, 0, 1\). The even polynomial \(f(x)=x^2(x-1)(x+1)=x^4-x^2\) has exactly those three distinct real zeros.

Answer

1) If \(f(x_0)=0\), then \(f(-x_0)=0\). 2) The function must have the zero \(x=0\). 3) One possible rule is \(f(x)=x^4-x^2\).
52184011
Let \(g\) be an odd polynomial. 1) Prove that \(g(0)=0\). 2) Explain why \(g\) cannot have exactly two distinct real zeros. 3) If \(x=4\) is a zero, list all additional zeros that the symmetry requires.

Hints

- Substitute \(x=0\) into the odd-function identity. - Determine what symmetry does to a nonzero x-intercept. - Count the origin together with opposite pairs.

Solution

1. Odd symmetry gives \(g(-x)=-g(x)\). Setting \(x=0\) yields \(g(0)=-g(0)\), so \(2g(0)=0\) and \(g(0)=0\). 2. Every nonzero zero \(x_0\) has a matching zero \(-x_0\), while \(0\) is always a zero. Thus, the number of distinct real zeros is \(1\) plus an even number, so it cannot equal \(2\). 3. Since \(4\) is a zero, \(-4\) is also a zero. The function must also have the zero \(0\).

Answer

1) \(g(0)=0\) 2) Its distinct real zeros consist of \(0\) and zero or more opposite pairs, so the total cannot be \(2\). 3) The additional required zeros are \(-4\) and \(0\).
52187911
Let \(f(x)=2ax^4+(b-1)x^3+cx^2+4x\). Find \(a\), \(b\), and \(c\) so that \(f\) is odd and its graph passes through \((1, 6)\).

Hints

- Set the coefficients of all even-power terms equal to \(0\). - Substitute the coordinates of the given point. - Solve the remaining linear equation.

Solution

1. For \(f\) to be odd, the coefficients of the even-power terms must be \(0\). Thus, \(2a=0\) and \(c=0\), so \(a=0\) and \(c=0\). 2. The function becomes \(f(x)=(b-1)x^3+4x\). 3. Since \((1, 6)\) lies on the graph, \(6=(b-1)+4=b+3\). 4. Therefore, \(b=3\).

Answer

\(a=0\), \(b=3\), and \(c=0\)
52190511
Determine algebraically whether each function is even, odd, or neither. a) \(f(x)=\frac{x^2+3}{x^4}\) b) \(g(x)=x|x|\) c) \(h(x)=e^x+e^{-x}\) d) \(k(x)=x^3-x+1\)

Hints

- Replace \(x\) with \(-x\) in each rule. - Use \(|-x|=|x|\). - Compare the result with both the original function and its negative.

Solution

1. For \(f\), \(f(-x)=\frac{(-x)^2+3}{(-x)^4}=f(x)\). Its domain excludes \(0\) but is symmetric about \(0\), so \(f\) is even. 2. Since \(|-x|=|x|\), \(g(-x)=(-x)|-x|=-x|x|=-g(x)\). Thus, \(g\) is odd. 3. \(h(-x)=e^{-x}+e^x=h(x)\), so \(h\) is even. 4. \(k(-x)=-x^3+x+1\). This is neither \(k(x)=x^3-x+1\) nor \(-k(x)=-x^3+x-1\), so \(k\) is neither even nor odd.

Answer

a) Even b) Odd c) Even d) Neither even nor odd
52200511
Let \(f(x)=\frac{x^2+3x}{x^2+4}\). Determine algebraically whether its graph is symmetric about the y-axis, symmetric about the origin, or neither.

Hints

- Compute \(f(-x)\) carefully. - Compare it first with \(f(x)\), then with \(-f(x)\). - A symmetry identity must hold for every value in the domain.

Solution

1. Substitute \(-x\): \(f(-x)=\frac{x^2-3x}{x^2+4}\). 2. This is not equal to \(f(x)=\frac{x^2+3x}{x^2+4}\) for all \(x\), so \(f\) is not even. 3. Also, \(-f(x)=\frac{-x^2-3x}{x^2+4}\), which is not equal to \(f(-x)\) for all \(x\). Therefore, \(f\) is not odd. 4. The graph has neither symmetry.

Answer

The graph is neither symmetric about the y-axis nor symmetric about the origin.
52288111
Let \(f(x)=0.4x^n\), where \(n\) is a positive integer. Describe the symmetry, intervals of increase or decrease, and range of \(f\) for even values of \(n\) and for odd values of \(n\).

Hints

- Consider even and odd exponents separately. - Compare \(f(-x)\) with \(f(x)\) and \(-f(x)\). - Use the shapes of familiar graphs such as \(y=x^2\) and \(y=x^3\). - Determine which output values are possible in each case.

Solution

1. If \(n\) is even, then \(f(-x)=0.4(-x)^n=0.4x^n=f(x)\), so \(f\) is even and its graph is symmetric about the y-axis. The function decreases on \((-\infty, 0]\) and increases on \([0, \infty)\). Its range is \([0, \infty)\). 2. If \(n\) is odd, then \(f(-x)=0.4(-x)^n=-0.4x^n=-f(x)\), so \(f\) is odd and its graph has rotational symmetry about the origin. The function increases on \((-\infty, \infty)\), and its range is \((-\infty, \infty)\).

Answer

Even \(n\): even; symmetric about the y-axis; decreasing on \((-\infty, 0]\); increasing on \([0, \infty)\); range \([0, \infty)\). Odd \(n\): odd; rotational symmetry about the origin; increasing on \((-\infty, \infty)\); range \((-\infty, \infty)\).
52288211
Consider the family of power functions \(p(x)=ax^n\), where \(a\ne 0\) is real and \(n\) is a positive integer. a) Determine the conditions on \(a\) and \(n\) that make \(p\) strictly decreasing over its entire domain. b) Does replacing \(a\) with \(-a\) change the graph's type of symmetry? Justify your answer.

Hints

- Compare the overall behavior of \(x^2\) and \(x^3\). - Think about how multiplying all function values by a negative number changes a graph. - Use the definitions of even and odd functions to determine whether the sign of \(a\) affects symmetry.

Solution

1. For odd \(n\), \(x^n\) is strictly increasing on all real numbers. Multiplying by a negative coefficient reverses the order of the outputs, so \(ax^n\) is strictly decreasing exactly when \(n\) is odd and \(a<0\). For even \(n\), the function changes direction at \(x=0\), so it cannot be strictly decreasing over its entire domain. 2. Replacing \(a\) with \(-a\) reflects the graph across the x-axis. The parity of \(n\), not the sign of \(a\), determines the symmetry. When \(n\) is even, both graphs are symmetric about the y-axis. When \(n\) is odd, both graphs have rotational symmetry about the origin.

Answer

a) \(n\) must be odd and \(a<0\). b) No. Replacing \(a\) with \(-a\) reflects the graph across the x-axis but preserves y-axis symmetry for even \(n\) and origin symmetry for odd \(n\).
52315911
The polynomial function \(f\) is defined by \(f(x) = 2x^4 + (a + 3)x^3 - 5x^2\). Find the value of \(a \in \mathbb{R}\) that makes the graph symmetric about the y-axis. Verify your answer using the condition \(f(-x) = f(x)\).

Hints

- Recall which powers can appear in an even polynomial function. - Determine which coefficient must equal zero. - Substitute \(-x\) for \(x\) to verify the even-function condition.

Solution

1. A polynomial is even only when the coefficients of all odd-power terms are zero. 2. The coefficient of \(x^3\) must be zero, so \(a + 3 = 0\). Therefore, \(a = -3\). 3. Substituting \(a = -3\) gives \(f(x) = 2x^4 - 5x^2\). 4. Then \(f(-x) = 2(-x)^4 - 5(-x)^2 = 2x^4 - 5x^2 = f(x)\). Therefore, the graph is symmetric about the y-axis.

Answer

\(a = -3\)
52316011
Consider \(g(x) = \frac{1}{2}x^5 - 4x^3 + x\). 1. Determine algebraically whether the graph of \(g\) is symmetric about the origin. 2. Decide whether \(h(x) = g(x) + 5\) is also symmetric about the origin. Justify your answer using the symmetry condition.

Hints

- Recall the equation that defines an odd function. - Track the sign of each term after substituting \(-x\) for \(x\). - Determine how adding the constant \(5\) affects the equation \(h(-x) = -h(x)\).

Solution

1. Substitute \(-x\): \(g(-x) = \frac{1}{2}(-x)^5 - 4(-x)^3 + (-x) = -\frac{1}{2}x^5 + 4x^3 - x\). 2. This expression equals \(-g(x)\), so \(g(-x) = -g(x)\). Therefore, \(g\) is odd and its graph is symmetric about the origin. 3. For \(h(x) = g(x) + 5\), \(h(-x) = g(-x) + 5 = -g(x) + 5\). 4. However, \(-h(x) = -g(x) - 5\). Since \(h(-x) \ne -h(x)\), \(h\) is not odd and its graph is not symmetric about the origin.

Answer

1. Yes. \(g(-x) = -g(x)\), so \(g\) is symmetric about the origin. 2. No. \(h(-x) = -g(x) + 5\), while \(-h(x) = -g(x) - 5\).
52316411
Consider \(g(x) = (a - 1)x^4 + 2x^3 + (b + 3)x^2 + c\). a) Find \(a\), \(b\), and \(c\) so that the graph of \(g\) is symmetric about the origin. b) Explain why no values of \(a\), \(b\), and \(c\) make the graph symmetric about the y-axis.

Hints

- Identify which powers are even and which are odd. - Determine which coefficients can be changed by choosing \(a\), \(b\), and \(c\). - A term disappears only when its coefficient is zero.

Solution

1. For symmetry about the origin, \(g\) must be odd. Therefore, the coefficients of the even-power terms must be zero. 2. Set \(a - 1 = 0\), \(b + 3 = 0\), and \(c = 0\). This gives \(a = 1\), \(b = -3\), and \(c = 0\). 3. The resulting function is \(g(x) = 2x^3\), which is odd. 4. For symmetry about the y-axis, \(g\) would have to be even, so every odd-power term would need coefficient zero. 5. The coefficient of \(x^3\) is fixed at \(2\), so that term cannot be eliminated. Therefore, no parameter values make \(g\) even.

Answer

a) \(a = 1\), \(b = -3\), and \(c = 0\) b) No such values exist because the fixed term \(2x^3\) prevents the function from being even.
52316711
A function has the form \(f(x) = ax^n + c\), where \(a, c \in \mathbb{R}\) and \(n\) is a positive integer. Determine the conditions on \(a\), \(n\), and \(c\) so that all three statements are true: 1. The graph of \(f\) is symmetric about the y-axis. 2. The graph has y-intercept \((0, 4)\). 3. \(f(x) \to -\infty\) as \(x \to \infty\).

Hints

- Determine which exponents make \(ax^n + c\) an even function. - Evaluate \(f(0)\) to find the y-intercept. - Consider how the sign of \(a\) affects the end behavior when \(n\) is even.

Solution

1. Symmetry about the y-axis requires \(f\) to be even, so \(n\) must be a positive even integer. 2. The y-intercept is determined by \(f(0) = c\). Therefore, \(c = 4\). 3. For a positive even exponent, \(x^n \to \infty\) as \(x \to \infty\). To make \(ax^n + c \to -\infty\), the leading coefficient must satisfy \(a < 0\).

Answer

\(n \in \{2, 4, 6, \ldots\}\), \(c = 4\), and \(a < 0\)
52316811
A polynomial function has the form \(f(x) = ax^3 + bx^2 + cx + d\). a) What must be true about \(b\) and \(d\) for the graph of \(f\) to be symmetric about the origin? Briefly explain. b) Under the condition from part a), find \(a\) and \(c\) if the graph passes through \(P(1, 5)\) and \(Q(2, 22)\).

Hints

- Recall the relationship between origin symmetry and odd functions. - Substitute each point into the function equation. - Solve the resulting system of two linear equations.

Solution

1. Symmetry about the origin means that \(f\) is odd, so only odd powers of \(x\) may have nonzero coefficients. Therefore, \(b = 0\) and \(d = 0\). 2. The function becomes \(f(x) = ax^3 + cx\). Substituting \(P(1, 5)\) gives \(a + c = 5\). 3. Substituting \(Q(2, 22)\) gives \(8a + 2c = 22\), or \(4a + c = 11\). 4. Subtracting \(a + c = 5\) from \(4a + c = 11\) gives \(3a = 6\), so \(a = 2\). 5. Then \(2 + c = 5\), so \(c = 3\).

Answer

a) \(b = 0\) and \(d = 0\), because an odd polynomial contains only odd powers of \(x\). b) \(a = 2\) and \(c = 3\)
52317111
Let \(f(x) = 2x^n + cx^3\), where \(n\) is a positive integer and \(c\) is a real number. The graph of \(f\) must be symmetric about the origin. Its leading term must also be \(-4x^3\), so its end behavior matches that of \(g(x) = -4x^3\). Find all possible values of \(n\) and \(c\).

Hints

- Use the relationship between origin symmetry and odd functions. - Identify which term determines the end behavior. - Consider the cases \(n < 3\), \(n = 3\), and \(n > 3\). - When \(n = 3\), combine the like terms.

Solution

1. Symmetry about the origin requires \(f\) to be odd, so \(n\) must be odd. 2. The leading term must have degree \(3\) and leading coefficient \(-4\). 3. If \(n = 1\), then \(f(x) = 2x + cx^3\). The leading term is \(cx^3\), so \(c = -4\). 4. If \(n = 3\), then \(f(x) = (2 + c)x^3\). Setting \(2 + c = -4\) gives \(c = -6\). 5. If \(n \ge 5\) is odd, then \(2x^n\) has degree greater than \(3\) and becomes the leading term, so the required end behavior is impossible.

Answer

\((n, c) = (1, -4)\) or \((n, c) = (3, -6)\)
52317211
Let \(h(x) = ax^4 + 5x^m\), where \(a\) is a real number and \(m\) is a nonnegative integer. The graph of \(h\) must be symmetric about the y-axis. Its leading term must also be \(5x^4\), so its end behavior matches that of \(p(x) = 5x^4\). Find all possible pairs \((a, m)\).

Hints

- Use the relationship between y-axis symmetry and even functions. - Identify which term determines the end behavior. - Consider the cases \(m < 4\), \(m = 4\), and \(m > 4\). - Remember that \(0\) is an even exponent.

Solution

1. Symmetry about the y-axis requires \(h\) to be even, so \(m\) must be even. 2. If \(m < 4\), then \(m = 0\) or \(m = 2\). The term \(ax^4\) is the leading term, so \(a = 5\). 3. If \(m = 4\), then \(h(x) = (a + 5)x^4\). Setting \(a + 5 = 5\) gives \(a = 0\). 4. If \(m > 4\), then the term \(5x^m\) has degree greater than \(4\), so the leading term cannot be \(5x^4\).

Answer

\((a, m) = (5, 0)\), \((5, 2)\), or \((0, 4)\)
52318011
Let \(p(x) = \frac{1}{4}x^5 - 2x^3\). a) Show algebraically that the graph of \(p\) is symmetric about the origin. b) Describe the symmetry of the graph of \(q(x) = p(x) + 3\). Justify your answer.

Hints

- Use the condition \(f(-x) = -f(x)\) for origin symmetry. - Simplify powers with odd exponents. - Interpret adding \(3\) as a vertical translation. - Track how a vertical translation changes the center of symmetry.

Solution

1. Substitute \(-x\) for \(x\): \(p(-x) = \frac{1}{4}(-x)^5 - 2(-x)^3\). 2. Because \(5\) and \(3\) are odd, \(p(-x) = -\frac{1}{4}x^5 + 2x^3 = -p(x)\). Therefore, the graph of \(p\) is symmetric about the origin. 3. The function \(q(x) = p(x) + 3\) is the graph of \(p\) shifted up \(3\) units. 4. Since \(q(-x) - 3 = p(-x) = -p(x) = -(q(x) - 3)\), the graph of \(q\) is symmetric about the point \((0, 3)\). It is not symmetric about the origin or the y-axis.

Answer

a) \(p(-x) = -p(x)\), so the graph is symmetric about the origin. b) The graph of \(q\) is symmetric about \((0, 3)\).
52318111
The graph of \(f\) is symmetric about the origin. Determine algebraically whether each new function is even or odd. a) \(g(x) = x f(x)\) b) \(h(x) = (f(x))^2\) c) \(k(x) = \frac{1}{2}f(x)\)

Hints

- Begin with \(f(-x) = -f(x)\). - Substitute \(-x\) into each new function. - Compare each result with the original function and its opposite. - Recall that squaring a negative expression gives the same result as squaring the positive expression.

Solution

1. Because \(f\) is odd, \(f(-x) = -f(x)\). 2. For \(g\), \(g(-x) = (-x)f(-x) = (-x)(-f(x)) = xf(x) = g(x)\). Therefore, \(g\) is even. 3. For \(h\), \(h(-x) = (f(-x))^2 = (-f(x))^2 = (f(x))^2 = h(x)\). Therefore, \(h\) is even. 4. For \(k\), \(k(-x) = \frac{1}{2}f(-x) = -\frac{1}{2}f(x) = -k(x)\). Therefore, \(k\) is odd.

Answer

a) Even; the graph is symmetric about the y-axis. b) Even; the graph is symmetric about the y-axis. c) Odd; the graph is symmetric about the origin.
52318711
a) Let \(f\) be an even polynomial function. Determine algebraically whether \(g(x) = xf(x)\) is even or odd. b) Determine whether each constant function is even, odd, both, or neither: \(h(x) = 5\) and \(k(x) = 0\).

Hints

- Use \(f(-x) = f(x)\) for an even function. - Substitute \(-x\) into each function. - Compare the result with both the original function and its opposite. - Pay special attention to the fact that \(-0 = 0\).

Solution

1. Since \(f\) is even, \(f(-x) = f(x)\). Therefore, \(g(-x) = (-x)f(-x) = -xf(x) = -g(x)\), so \(g\) is odd. 2. For \(h(x) = 5\), \(h(-x) = 5 = h(x)\), so \(h\) is even. However, \(h(-x) = 5 \ne -5 = -h(x)\), so \(h\) is not odd. 3. For \(k(x) = 0\), \(k(-x) = 0 = k(x)\) and \(k(-x) = 0 = -k(x)\). Therefore, the zero function is both even and odd.

Answer

a) \(g\) is odd; its graph is symmetric about the origin. b) \(h(x) = 5\) is even but not odd. \(k(x) = 0\) is both even and odd.
52318811
a) The polynomial functions \(p\) and \(q\) are both odd. Prove that their sum \(s(x) = p(x) + q(x)\) is also odd. b) The function \(f(x) = x^3 - 4x\) is shifted up \(3\) units to create \(h\). Determine algebraically whether \(h\) is still odd.

Hints

- Use the defining equation for an odd function. - Substitute \(-x\) into the sum and factor out \(-1\). - A vertical shift changes the function by adding a constant. - Compare \(h(-x)\) directly with \(-h(x)\).

Solution

1. Since \(p\) and \(q\) are odd, \(p(-x) = -p(x)\) and \(q(-x) = -q(x)\). 2. Then \(s(-x) = p(-x) + q(-x) = -p(x) - q(x) = -(p(x) + q(x)) = -s(x)\). Therefore, \(s\) is odd. 3. The shifted function is \(h(x) = x^3 - 4x + 3\). 4. Substituting \(-x\) gives \(h(-x) = -x^3 + 4x + 3\), while \(-h(x) = -x^3 + 4x - 3\). 5. Since \(h(-x) \ne -h(x)\), the shifted function is not odd.

Answer

a) \(s\) is odd because \(s(-x) = -s(x)\). b) No. The function \(h(x) = x^3 - 4x + 3\) is not odd.
52319211
A graph is symmetric about the point \((2, 0)\) when \(g(2 + h) = -g(2 - h)\) for every real number \(h\). Verify algebraically that \(g(x) = x^3 - 6x^2 + 12x - 8\) has this symmetry.

Hints

- Try rewriting the polynomial as a binomial cube. - Substitute \(2 + h\) and \(2 - h\) for \(x\). - Simplify each expression before comparing them. - Remember that the negative sign applies to the entire expression \(g(2 - h)\).

Solution

1. Factor the polynomial: \(g(x) = (x - 2)^3\). 2. Evaluate the function to the right of \(x = 2\): \(g(2 + h) = (2 + h - 2)^3 = h^3\). 3. Evaluate the function the same distance to the left: \(g(2 - h) = (2 - h - 2)^3 = (-h)^3 = -h^3\). 4. Therefore, \(g(2 + h) = h^3 = -g(2 - h)\), so the graph is symmetric about \((2, 0)\).

Answer

\(g(2 + h) = h^3\) and \(g(2 - h) = -h^3\), so \(g(2 + h) = -g(2 - h)\). The graph is symmetric about \((2, 0)\).
52328111
Determine algebraically whether each polynomial function is even, odd, or neither. 1. \(f(x) = 4x^6 - x^2 + 3\) 2. \(g(x) = -2x^3 - 5x\) 3. \(h(x) = x^4 + x\)

Hints

- Substitute \(-x\) for every occurrence of \(x\). - Track the signs of even and odd powers. - Compare each result with both the original function and its opposite. - Treat a constant as a term with exponent \(0\).

Solution

1. \(f(-x) = 4(-x)^6 - (-x)^2 + 3 = 4x^6 - x^2 + 3 = f(x)\). Therefore, \(f\) is even. 2. \(g(-x) = -2(-x)^3 - 5(-x) = 2x^3 + 5x = -g(x)\). Therefore, \(g\) is odd. 3. \(h(-x) = (-x)^4 + (-x) = x^4 - x\). This is neither \(h(x) = x^4 + x\) nor \(-h(x) = -x^4 - x\). Therefore, \(h\) is neither even nor odd.

Answer

1. Even; the graph is symmetric about the y-axis. 2. Odd; the graph is symmetric about the origin. 3. Neither even nor odd.
52328911
Consider \(f(x) = x^4 + (k - 5)x^3 + mx^2 + (2k - 10)x + 3\). Find all values of \(k\) and \(m\) for which \(f\) is even.

Hints

- Identify the terms with odd exponents. - An even polynomial must have coefficient \(0\) on every odd-power term. - Check whether one value of \(k\) satisfies both odd-power conditions. - Decide whether the coefficient of an even-power term affects evenness.

Solution

1. An even polynomial has no nonzero odd-power terms. 2. Set the coefficient of \(x^3\) equal to zero: \(k - 5 = 0\), so \(k = 5\). 3. With \(k = 5\), the coefficient of \(x\) is \(2k - 10 = 2(5) - 10 = 0\). 4. The term \(mx^2\) has an even exponent, so \(m\) may be any real number.

Answer

\(k = 5\) and \(m\) may be any real number.
52329011
Let \(g(x) = (x + a)x(x - 6)\). a) Find \(a\) so that \(g\) is odd. b) Verify your answer algebraically using the definition of an odd function.

Hints

- Expand the product completely. - Identify the even-power term. - An odd polynomial cannot have a nonzero even-power term. - Substitute \(-x\) into the resulting function to verify the definition.

Solution

1. Expand the expression: \(g(x) = x^3 + (a - 6)x^2 - 6ax\). 2. For \(g\) to be odd, the coefficient of the even-power term \(x^2\) must be zero. Thus, \(a - 6 = 0\), so \(a = 6\). 3. With \(a = 6\), \(g(x) = x^3 - 36x\). 4. Then \(g(-x) = (-x)^3 - 36(-x) = -x^3 + 36x = -(x^3 - 36x) = -g(x)\). Therefore, \(g\) is odd.

Answer

a) \(a = 6\) b) For \(a = 6\), \(g(-x) = -g(x)\), so the graph is symmetric about the origin.
52329711
Disprove the statement with a counterexample: “If a polynomial function is odd, then it has exactly one real zero.” Give a polynomial function that is odd and find all of its real zeros.

Hints

- An odd polynomial may contain only odd powers of \(x\). - To disprove a statement, one valid counterexample is enough. - Look for a polynomial from which you can factor out \(x\). - A cubic polynomial can have as many as three real zeros.

Solution

1. Consider \(f(x) = x^3 - x\). Since \(f(-x) = -f(x)\), the function is odd. 2. Factor the polynomial: \(f(x) = x(x^2 - 1) = x(x - 1)(x + 1)\). 3. By the zero-product property, the real zeros are \(x = -1\), \(x = 0\), and \(x = 1\). 4. This odd polynomial has three real zeros, so the statement is false.

Answer

One counterexample is \(f(x) = x^3 - x\). Its real zeros are \(-1\), \(0\), and \(1\), so it does not have exactly one real zero.
52454311
Let \(f(x)=x^3\) and \(g(x)=-x^3\). a) Complete the value table. <table> <tr> <td>\(x\)</td> <td>\(-2\)</td> <td>\(-1\)</td> <td>\(0\)</td> <td>\(1\)</td> <td>\(2\)</td> </tr> <tr> <td>\(f(x)\)</td> <td>...</td> <td>...</td> <td>...</td> <td>...</td> <td>...</td> </tr> <tr> <td>\(g(x)\)</td> <td>...</td> <td>...</td> <td>...</td> <td>...</td> <td>...</td> </tr> </table> b) Describe a geometric transformation that maps the graph of \(f\) onto the graph of \(g\). c) Determine algebraically whether \(g\) is even, odd, or neither.

Hints

- Track the sign of a negative number raised to the third power. - Compare the outputs of the two functions for the same input. - Use the tests \(g(-x)=g(x)\) for even functions and \(g(-x)=-g(x)\) for odd functions. - What does a negative sign in front of the entire function do to its graph?

Solution

1. For \(f(x)=x^3\), the values are \(-8,-1,0,1,8\) for \(x=-2,-1,0,1,2\), respectively. 2. For \(g(x)=-x^3\), the values are \(8,1,0,-1,-8\). 3. Multiplying every output of \(f\) by \(-1\) reflects its graph across the x-axis, producing the graph of \(g\). Because \(f\) is odd, reflecting across the y-axis also gives the same graph. 4. \(g(-x)=-(-x)^3=x^3\), while \(-g(x)=-(-x^3)=x^3\). Therefore, \(g(-x)=-g(x)\), so \(g\) is odd.

Answer

a) \(f(x): -8,-1,0,1,8\); \(g(x): 8,1,0,-1,-8\) b) Reflect the graph of \(f\) across the x-axis. For this function, reflection across the y-axis gives the same result. c) \(g\) is odd because \(g(-x)=-g(x)\).
52454411
A power function has the form \(h(x)=ax^3\), and its graph passes through \(P(2, 4)\). a) Find \(a\). b) Evaluate \(h(-3)\). c) Another function, \(k(x)=bx^3\), passes through \(Q(1, -2)\). Compare its graph with the graph of \(h\): identify the quadrants containing the graph of \(k\), and describe a reflection and vertical stretch that map the graph of \(h\) onto the graph of \(k\).

Hints

- Use the given point to solve for the unknown coefficient. - Evaluate the power before multiplying by the coefficient. - Compare \(k(x)\) directly with \(h(x)\) by writing \(k(x)=ch(x)\). - How does a negative coefficient affect an odd function?

Solution

1. Substitute \((2, 4)\): \(4=a(2^3)=8a\), so \(a=\frac{1}{2}\). 2. \(h(-3)=\frac{1}{2}(-3)^3=\frac{1}{2}(-27)=-13.5\). 3. Substitute \((1, -2)\) into \(k(x)=bx^3\): \(-2=b(1^3)\), so \(b=-2\). 4. Since \(k(x)=-2x^3=-4\left(\frac{1}{2}x^3\right)=-4h(x)\), reflect the graph of \(h\) across the x-axis and stretch it vertically by a factor of \(4\). The graph of \(k\) lies in Quadrants II and IV and passes through the origin.

Answer

a) \(a=\frac{1}{2}\) b) \(h(-3)=-13.5\) c) \(k(x)=-4h(x)\). Reflect the graph of \(h\) across the x-axis and stretch it vertically by a factor of \(4\). The graph lies in Quadrants II and IV and passes through the origin.
52583911
Let \(f(x)=u(v(x))\). a) Show that if \(u\) is even and \(v\) is odd, then \(f\) is even. b) Determine the symmetry of \(f\) if both \(u\) and \(v\) are odd. Prove your answer. c) Give an example in which \(v\) is neither even nor odd, but \(f=u\circ v\) is even.

Hints

- Use the definitions \(f(-x)=f(x)\) for even functions and \(f(-x)=-f(x)\) for odd functions. - Substitute \(-x\) into the inner function first. - For part c, try using an outer function that reverses a horizontal shift.

Solution

1. If \(v\) is odd, then \(v(-x)=-v(x)\). If \(u\) is even, then \(u(-v(x))=u(v(x))\). Therefore, \(f(-x)=u(v(-x))=u(-v(x))=u(v(x))=f(x)\), so \(f\) is even. 2. If both functions are odd, then \(f(-x)=u(v(-x))=u(-v(x))=-u(v(x))=-f(x)\). Therefore, \(f\) is odd. 3. For example, let \(v(x)=x+1\), which is neither even nor odd, and let \(u(x)=(x-1)^2\). Then \(f(x)=u(v(x))=((x+1)-1)^2=x^2\), which is even.

Answer

a) \(f\) is even. b) \(f\) is odd. c) One example is \(v(x)=x+1\) and \(u(x)=(x-1)^2\), which give \(f(x)=x^2\).
52584011
Symmetry can be preserved or created through function operations. a) Explain why \(h(x)=f(x^4+1)\) is even for every function \(f\) for which the composition is defined. b) Let \(k(x)=(g(x))^2\). Show that \(k\) is even whenever \(g\) is either even or odd. c) For an arbitrary function \(g\), show that \(s(x)=g(x)g(-x)\) is even wherever both factors are defined.

Hints

- Replace \(x\) with \(-x\) and simplify. - Consider the even and odd cases for \(g\) separately in part b. - Use the commutative property of multiplication in part c.

Solution

1. The inner function \(x^4+1\) is even because \((-x)^4+1=x^4+1\). Therefore, \(h(-x)=f((-x)^4+1)=f(x^4+1)=h(x)\). 2. If \(g\) is even, then \(k(-x)=(g(-x))^2=(g(x))^2=k(x)\). If \(g\) is odd, then \(k(-x)=(-g(x))^2=(g(x))^2=k(x)\). Thus \(k\) is even in either case. 3. \(s(-x)=g(-x)g(-(-x))=g(-x)g(x)=g(x)g(-x)=s(x)\). Therefore, \(s\) is even.

Answer

a) \(h(-x)=h(x)\), so \(h\) is even. b) Squaring removes the possible negative sign, so \(k(-x)=k(x)\). c) \(s(-x)=g(-x)g(x)=s(x)\), so \(s\) is even.
52643511
Consider the family of functions \(f_t(x)=e^{tx}+e^{-tx}\), where \(t\in\mathbb{R}\setminus\{0\}\). a) Show algebraically that every graph is symmetric about the y-axis. b) A graph passes through \((2, e^4+e^{-4})\). Find all possible values of \(t\).

Hints

- Test whether \(f_t(-x)=f_t(x)\). - Substitute the given point into the function. - Notice the symmetry between the positive and negative exponents. - Check whether more than one parameter value works.

Solution

1. Evaluate the function at \(-x\): \(f_t(-x)=e^{-tx}+e^{tx}=f_t(x)\). Therefore, each function is even and its graph is symmetric about the y-axis. 2. The point condition gives \(e^{2t}+e^{-2t}=e^4+e^{-4}\). 3. Let \(u=e^{2t}>0\). Then \(u+\frac{1}{u}=e^4+e^{-4}\), whose positive solutions are \(u=e^4\) and \(u=e^{-4}\). 4. Thus, \(2t=4\) or \(2t=-4\), giving \(t=2\) or \(t=-2\).

Answer

a) \(f_t(-x)=f_t(x)\), so each graph is symmetric about the y-axis. b) \(t=2\) or \(t=-2\)
52750411
Determine whether \(g(x)=\frac{\sqrt{x^4+1}}{x^3}\) is even, odd, or neither.

Hints

- Determine the domain before testing symmetry. - Compare the effects of \(-x\) on the fourth and third powers. - Check whether the result equals \(g(x)\) or \(-g(x)\).

Solution

1. The denominator requires \(x\ne0\), while \(x^4+1>0\) for every real \(x\). Thus, the domain is \(\mathbb{R}\setminus\{0\}\), which is symmetric about \(0\). 2. Substitute \(-x\): \(g(-x)=\frac{\sqrt{(-x)^4+1}}{(-x)^3}=\frac{\sqrt{x^4+1}}{-x^3}=-g(x)\). 3. Therefore, \(g\) is odd.

Answer

The function is odd, so its graph is symmetric about the origin.
52828611
A power function has the form \(h(x) = x^n\). a) Use the table to determine \(n\). b) Use the table to identify the symmetry of the graph. c) Complete the missing entries. <table> <tr><td>\(x\)</td><td>\(h(x)\)</td></tr> <tr><td>\(0.5\)</td><td>\(0.0009765625\)</td></tr> <tr><td>\(-0.5\)</td><td>\(0.0009765625\)</td></tr> <tr><td>\(2\)</td><td>\(1024\)</td></tr> <tr><td>\(-2\)</td><td></td></tr> <tr><td></td><td>\(59{,}049\)</td></tr> <tr><td>\(-3\)</td><td></td></tr> </table>

Hints

- Compare the function values at \(0.5\) and \(-0.5\). - Use the point \((2, 1024)\) to solve for the exponent. - Decide whether the exponent is even or odd. - Use symmetry to complete the remaining entries.

Solution

1. From \(h(2) = 1024\), solve \(2^n = 1024\). Since \(1024 = 2^{10}\), \(n = 10\). 2. The table shows \(h(0.5) = h(-0.5)\). Since \(n = 10\) is even, \(h(-x) = h(x)\), so the graph is symmetric about the y-axis. 3. By symmetry, \(h(-2) = h(2) = 1024\). 4. Since \(3^{10} = 59{,}049\), the missing positive input is \(3\). 5. By symmetry, \(h(-3) = h(3) = 59{,}049\).

Answer

a) \(n = 10\) b) The graph is symmetric about the y-axis. c) The missing entries, from top to bottom, are \(1024\), \(3\), and \(59{,}049\).
52904511
Let \(f(x)=(x-5)^3+4(x-5)-2\). Find the center of symmetry \((x_0, y_0)\) of the graph and verify the point symmetry algebraically.

Hints

- Identify the translated odd parent expression. - For symmetry about \((x_0, y_0)\), compare points equally far to the left and right of \(x_0\). - Verify \(f(x_0+h)+f(x_0-h)=2y_0\).

Solution

1. The function is obtained from the odd function \(u^3+4u\) by shifting right \(5\) units and down \(2\) units. Therefore, the center of symmetry is \((5, -2)\). 2. For point symmetry about \((5, -2)\), verify that \(f(5+h)+f(5-h)=2(-2)\) for every real \(h\). 3. \(f(5+h)=h^3+4h-2\), and \(f(5-h)=-h^3-4h-2\). 4. Their sum is \(-4=2(-2)\), so the graph is symmetric about \((5, -2)\).

Answer

The center of symmetry is \((5, -2)\). Since \(f(5+h)+f(5-h)=-4\) for every real \(h\), the symmetry is verified.
52904611
Let \(g(x)=x^3+3x^2+3x+5\). Show algebraically that its graph is symmetric about the point \((-1, 4)\).

Hints

- Try rewriting the polynomial as a shifted cubic. - Use the point-symmetry condition with inputs \(-1+h\) and \(-1-h\). - The sum of the two outputs should equal twice the y-coordinate of the center.

Solution

1. Point symmetry about \((-1, 4)\) requires \(g(-1+h)+g(-1-h)=8\) for every real \(h\). 2. Rewrite the function as \(g(x)=(x+1)^3+4\). 3. Then \(g(-1+h)=h^3+4\) and \(g(-1-h)=-h^3+4\). 4. Their sum is \(8=2(4)\), so the graph is symmetric about \((-1, 4)\).

Answer

\(g(-1+h)=h^3+4\) and \(g(-1-h)=-h^3+4\), so \(g(-1+h)+g(-1-h)=8\). Therefore, the graph is symmetric about \((-1, 4)\).
52905711
Let \(f(x)=x^3+(k-5)x^2-36x\). Choose \(k\) so that \(f\) is odd. State the symmetry and find all real zeros for that value of \(k\).

Hints

- Eliminate the even-power term. - Factor out \(x\) after substituting the parameter value. - Use the difference of squares.

Solution

1. For the polynomial to be odd, the coefficient of the even-power term must be \(0\): \(k-5=0\), so \(k=5\). 2. Then \(f(x)=x^3-36x\), which is odd and has a graph symmetric about the origin. 3. Factor the equation \(x^3-36x=0\): \(x(x^2-36)=x(x-6)(x+6)=0\). 4. The real zeros are \(-6\), \(0\), and \(6\).

Answer

\(k=5\); the graph is symmetric about the origin; the real zeros are \(x=-6, 0, 6\).
52905811
Let \(g(x)=x^4+(a+1)x-81\). Choose \(a\) so that \(g\) is even. State the symmetry and find all real zeros for that value of \(a\).

Hints

- Eliminate the odd-power term. - Set the resulting polynomial equal to \(0\). - Remember that an even power can produce two real roots.

Solution

1. For the polynomial to be even, the coefficient of the linear term must be \(0\): \(a+1=0\), so \(a=-1\). 2. Then \(g(x)=x^4-81\), which is even and has a graph symmetric about the y-axis. 3. Set \(x^4-81=0\). Then \(x^4=81\), so the real solutions are \(x=3\) and \(x=-3\).

Answer

\(a=-1\); the graph is symmetric about the y-axis; the real zeros are \(x=-3\) and \(x=3\).
52906311
For each polynomial, determine whether its graph is symmetric about the y-axis, symmetric about the origin, or neither. Then determine its end behavior as \(x\to\infty\) and \(x\to-\infty\). a) \(f(x)=-x^4+10x^2-5\) b) \(g(x)=0.5x^5-2x^3+x\) c) \(h(x)=-x^3+x^2-1\)

Hints

- Compare \(p(-x)\) with \(p(x)\) and \(-p(x)\). - A polynomial with only even powers is even; one with only odd powers is odd. - Use the leading term to determine the end behavior.

Solution

1. The function \(f\) contains only even powers of \(x\), so \(f(-x)=f(x)\). Its graph is symmetric about the y-axis. Its leading term is \(-x^4\), so both ends fall toward \(-\infty\). 2. The function \(g\) contains only odd powers of \(x\), so \(g(-x)=-g(x)\). Its graph is symmetric about the origin. Its leading term is \(0.5x^5\), so the left end falls and the right end rises. 3. The function \(h\) contains both even and odd powers, so it is neither even nor odd. Its leading term is \(-x^3\), so the left end rises and the right end falls.

Answer

a) Symmetric about the y-axis; \(\lim_{x\to\infty}f(x)=-\infty\) and \(\lim_{x\to-\infty}f(x)=-\infty\). b) Symmetric about the origin; \(\lim_{x\to\infty}g(x)=\infty\) and \(\lim_{x\to-\infty}g(x)=-\infty\). c) Neither; \(\lim_{x\to\infty}h(x)=-\infty\) and \(\lim_{x\to-\infty}h(x)=\infty\).
52945211
Consider the family of functions \(g_k(x)=x^3+kx^2-k^2x-k^3\), where \(k\in\mathbb{R}\setminus\{0\}\). a) Find all intercepts of the graph of \(g_k\). b) Show that the graphs of \(g_k\) and \(g_{-k}\) are images of each other under a \(180^\circ\) rotation about the origin.

Hints

- Try factoring by grouping. - Record the multiplicity of each zero. - Substitute \(-k\) into the original rule. - Compare \(g_{-k}(x)\) with \(-g_k(-x)\).

Solution

1. The y-intercept is \(g_k(0)=-k^3\), so it is \((0, -k^3)\). 2. Factor the function: \(g_k(x)=(x-k)(x+k)^2\). Thus the x-intercepts are \((k, 0)\) and \((-k, 0)\), with \(x=-k\) a double zero. 3. Replacing \(k\) by \(-k\) gives \(g_{-k}(x)=x^3-kx^2-k^2x+k^3\). 4. Also, \(-g_k(-x)=x^3-kx^2-k^2x+k^3\). Therefore, \(g_{-k}(x)=-g_k(-x)\), which proves that a \(180^\circ\) rotation about the origin maps one graph onto the other.

Answer

a) y-intercept: \((0, -k^3)\); x-intercepts: \((k, 0)\) and \((-k, 0)\), where \(x=-k\) is a double zero b) Since \(g_{-k}(x)=-g_k(-x)\), a \(180^\circ\) rotation about the origin maps one graph onto the other.
53216611
Consider \(f(x)=0.25x^4\). a) Calculate \(f(-2)\) and \(f(3)\). b) Find all real values of \(x\) for which \(f(x)=64\). c) Determine whether each statement is true or false. Justify your answer. (1) The graph of \(f\) is symmetric about the y-axis. (2) There is no real number \(x\) for which \(f(x)=-2\).
Figure for problem 532166

Hints

- Substitute the given inputs into the function rule. - An even-power equation with a positive result may have two opposite real solutions. - Compare \(f(-x)\) with \(f(x)\). - Determine the possible signs of \(x^4\).

Solution

1. \(f(-2)=0.25(-2)^4=4\), and \(f(3)=0.25(3^4)=20.25\). 2. Solve \(0.25x^4=64\). Multiplying by \(4\) gives \(x^4=256\), so \(x=-4\) or \(x=4\). 3. Statement (1) is true because \(f(-x)=f(x)\); the function is even. 4. Statement (2) is true because \(x^4\ge0\) for every real \(x\), so \(f(x)\ge0\).

Answer

a) \(f(-2)=4\) and \(f(3)=20.25\) b) \(x=-4\) and \(x=4\) c) (1) True (2) True
53231311
Consider \(f(x)=0.25x^3\). a) Find \(f(-2)\) and \(f(2)\). b) For what value of \(x\) is \(f(x)=54\)? c) Determine whether each statement is true or false. Briefly justify your answer. (1) The graph of \(f\) is symmetric about the origin. (2) There is no real \(x\) for which \(f(x)=-128\).
Figure for problem 532313

Hints

- Substitute the given inputs into the function rule. - Isolate \(x^3\), then take a cube root. - Use the odd-function test \(f(-x)=-f(x)\). - Test the second claim by solving the corresponding equation.

Solution

1. \(f(-2)=0.25(-2)^3=-2\), and \(f(2)=0.25(2^3)=2\). 2. Solve \(0.25x^3=54\). Multiplying by \(4\) gives \(x^3=216\), so \(x=6\). 3. Statement (1) is true because \(f(-x)=-f(x)\); the function is odd. 4. Statement (2) is false. Solving \(0.25x^3=-128\) gives \(x^3=-512\), so \(x=-8\).

Answer

a) \(f(-2)=-2\) and \(f(2)=2\) b) \(x=6\) c) (1) True (2) False; \(f(-8)=-128\)
53246711
Let \(f(x)=x^4-8x^3+20x^2-16x+3\). Its graph is shown. a) Verify algebraically that \(f(2+a)=f(2-a)\) for every real \(a\). b) Explain why this identity proves that the graph is symmetric about \(x=2\).
Figure for problem 532467

Hints

- Rewrite the polynomial using \(x-2\), or substitute both expressions directly. - Simplify the even powers of \(a\). - Interpret \(2+a\) and \(2-a\) geometrically.

Solution

1. Rewrite the polynomial in terms of \(x-2\): \(f(x)=(x-2)^4-4(x-2)^2+3\). 2. Substitute \(x=2+a\): \(f(2+a)=a^4-4a^2+3\). 3. Substitute \(x=2-a\): \(f(2-a)=(-a)^4-4(-a)^2+3=a^4-4a^2+3\). 4. Therefore, \(f(2+a)=f(2-a)\) for every real \(a\). 5. The inputs \(2+a\) and \(2-a\) are the same distance from \(2\). Equal outputs at every such pair mean that the graph is symmetric about the vertical line \(x=2\).

Answer

a) \(f(2+a)=f(2-a)=a^4-4a^2+3\) b) Points equally far to the left and right of \(x=2\) have equal y-values, so the graph is symmetric about \(x=2\).
53276411
Match each function to graph a, b, or c. First classify each function as even, odd, or neither. Then use symmetry, end behavior, or a key point to justify each match. \(f_1(x)=xe^{-x}\) \(f_2(x)=\frac{1}{2}x^3-\frac{3}{2}x\) \(f_3(x)=\frac{4}{x^2+1}-1\)
Figure for problem 532764

Hints

- Compute \(f(-x)\) for each function. - Compare \(f(-x)\) with both \(f(x)\) and \(-f(x)\). - Use one additional feature, such as an intercept or end behavior, to confirm each match.

Solution

1. For \(f_1\), \(f_1(-x)=-xe^x\), which is neither \(f_1(x)\) nor \(-f_1(x)\). Thus, \(f_1\) is neither even nor odd. Also, \(f_1(x)>0\) for \(x>0\), \(f_1(x)<0\) for \(x<0\), and \(f_1(x)\to0\) as \(x\to\infty\). These features match graph c. 2. For \(f_2\), \(f_2(-x)=-f_2(x)\), so \(f_2\) is odd. Its graph has rotational symmetry about the origin and passes through \((-1, 1)\), \((0, 0)\), and \((1, -1)\). These features match graph a. 3. For \(f_3\), \(f_3(-x)=f_3(x)\), so \(f_3\) is even. Its graph is symmetric about the y-axis, has y-intercept \((0, 3)\), and approaches the horizontal asymptote \(y=-1\). These features match graph b.

Answer

\(f_1\): neither; graph c \(f_2\): odd; graph a \(f_3\): even; graph b
53313811
Consider \(h(x)=-0.2x^3\). a) Find \(h(3)\) and \(h(-3)\). b) Find \(x\) when \(h(x)=-25\). c) Determine whether each statement is true or false. Briefly justify your answer. (1) As \(x\to\infty\), \(h(x)\to-\infty\). (2) \(h(a)+h(-a)=0\) for every real number \(a\).
Figure for problem 533138

Hints

- An odd power preserves the sign of its input before the coefficient is applied. - Use a cube root to solve an equation involving \(x^3\). - Consider how a negative leading coefficient affects the right-end behavior. - Relate \(h(a)+h(-a)=0\) to the definition of an odd function.

Solution

1. \(h(3)=-0.2(3^3)=-0.2(27)=-5.4\), and \(h(-3)=-0.2(-3)^3=-0.2(-27)=5.4\). 2. Solve \(-0.2x^3=-25\). Dividing by \(-0.2\) gives \(x^3=125\), so \(x=5\). 3. Statement (1) is true. The leading coefficient is negative and the degree is odd, so the right end of the graph falls without bound. 4. Statement (2) is true. Since \(h(-a)=-h(a)\), the function is odd and \(h(a)+h(-a)=0\).

Answer

a) \(h(3)=-5.4\) and \(h(-3)=5.4\) b) \(x=5\) c) (1) True (2) True
53346811
Consider \(f(x)=-0.25x^4\). 1. Describe the graph's shape and symmetry. 2. State the range of \(f\). 3. How would the symmetry and range change for \(g(x)=0.25x^3\)? Describe the differences without drawing a new graph.
Figure for problem 533468

Hints

- Compare the effects of even and odd exponents on symmetry. - Determine whether each function can have positive, negative, or all real outputs. - Use the sign of the coefficient to identify whether the even-power graph opens upward or downward.

Solution

1. The graph of \(f\) opens downward, has a maximum at \((0, 0)\), and is symmetric about the y-axis because its degree is even. 2. Since \(-0.25x^4\le0\), the range is \((-\infty, 0]\). 3. The function \(g\) has odd degree, so its graph is symmetric about the origin. Its outputs cover all real numbers, so its range is \((-\infty, \infty)\).

Answer

1. The graph opens downward, has a maximum at \((0, 0)\), and is symmetric about the y-axis. 2. \((-\infty, 0]\) 3. The graph of \(g\) is symmetric about the origin and has range \((-\infty, \infty)\).
53347811
The image shows three graphs labeled \(u\), \(v\), and \(w\). a) Match \(f(x)=x^2\), \(g(x)=x^4\), and \(h(x)=x^6\) to graphs \(u\), \(v\), and \(w\). Use their behavior near the origin to justify your answer. b) Show algebraically that \(Q(-1, 1)\) lies on all three graphs. c) State the common range of the three functions. Explain why no negative outputs occur.
Figure for problem 533478

Hints

- Compare the function values at an input such as \(0.5\). - Evaluate each function at \(x=-1\). - Determine the possible signs of even powers.

Solution

1. On \(-1<x<1\), a larger even exponent gives a value closer to zero. Therefore, graph \(w\) is \(h(x)=x^6\), graph \(v\) is \(g(x)=x^4\), and graph \(u\) is \(f(x)=x^2\). 2. \((-1)^2=1\), \((-1)^4=1\), and \((-1)^6=1\), so \((-1, 1)\) lies on all three graphs. 3. Every even power is nonnegative, and each function attains every nonnegative value. The common range is \([0, \infty)\).

Answer

a) Graph \(u\): \(f(x)=x^2\); graph \(v\): \(g(x)=x^4\); graph \(w\): \(h(x)=x^6\) b) \((-1)^2=(-1)^4=(-1)^6=1\) c) \([0, \infty)\)
53356011
Consider \(f(x)=0.5x^3\). a) Find \(f(-2)\) and \(f(3)\). b) For what value of \(x\) is \(f(x)=108\)? c) Determine whether each statement is true or false. Briefly justify your answer. (1) The graph is symmetric about the origin. (2) The equation \(f(x)=0\) has exactly one solution.
Figure for problem 533560

Hints

- An odd power keeps the sign of the input before the coefficient is applied. - Isolate \(x^3\) before taking a cube root. - Use the odd-function test \(f(-x)=-f(x)\). - Consider how many times a cubic of this form crosses the x-axis.

Solution

1. \(f(-2)=0.5(-2)^3=0.5(-8)=-4\), and \(f(3)=0.5(3^3)=13.5\). 2. Solve \(0.5x^3=108\). Dividing by \(0.5\) gives \(x^3=216\), so \(x=6\). 3. Statement (1) is true because \(f(-x)=-f(x)\); the function is odd. 4. Statement (2) is true because \(0.5x^3=0\) only when \(x=0\).

Answer

a) \(f(-2)=-4\) and \(f(3)=13.5\) b) \(x=6\) c) (1) True (2) True
53358811
The graph shows an even function \(f\), an odd function \(g\), and their sum \(h(x)=f(x)+g(x)\). a) Is \(h\) symmetric about the y-axis? Explain. b) Find \(h(0)\) using the graph of \(f\) and the symmetry of \(g\). c) Besides the origin, \(h\) has one more zero. Explain how to locate it using only the graphs of \(f\) and \(g\).
Figure for problem 533588

Hints

- Write \(h(-x)\) using the even and odd identities. - Recall the value of an odd function at \(0\). - A zero of the sum occurs when the two addends are opposites.

Solution

1. Since \(f\) is even and \(g\) is odd, \(h(-x)=f(x)-g(x)\), which is generally not equal to \(h(x)=f(x)+g(x)\). The displayed graph confirms that \(h\) is not symmetric about the y-axis. 2. Every odd function satisfies \(g(0)=0\). The graph shows \(f(0)=0\), so \(h(0)=f(0)+g(0)=0\). 3. A zero of \(h\) satisfies \(f(x)+g(x)=0\), or \(f(x)=-g(x)\). On the graph, look for an x-value where the two function values have equal magnitude and opposite signs. This occurs at \(x=-2.5\).

Answer

a) No. In general, \(h(-x)=f(x)-g(x)\ne h(x)\). b) \(h(0)=0\) c) Find where \(f(x)=-g(x)\). The additional zero is \(x=-2.5\).
53360211
A polynomial function has the form \(f(x) = ax^n + c\). Find \(a\), \(n\), and \(c\) so that all conditions are satisfied: - The graph is symmetric about the origin. - \(f(x) \to -\infty\) as \(x \to \infty\). - The graph passes through \((1, -2)\). - The positive integer exponent \(n\) is as small as possible.
Figure for problem 533602

Hints

- Use the relationship between origin symmetry and odd functions. - Determine what origin symmetry requires of the constant term. - Substitute the given point to find \(a\).

Solution

1. Symmetry about the origin requires \(f\) to be odd. Therefore, \(n\) must be odd and \(c = 0\). 2. For an odd exponent, \(f(x) \to -\infty\) as \(x \to \infty\) only when \(a < 0\). 3. Since \((1, -2)\) lies on the graph, \(-2 = a(1)^n\), so \(a = -2\). 4. The smallest positive odd integer is \(n = 1\). Thus, \(f(x) = -2x\).

Answer

\(a = -2\), \(n = 1\), and \(c = 0\)
53405511
The graph shown is an even fourth-degree polynomial \(f\). Find one possible rule using the marked points \(A(0, 2)\), \(B(1, 0)\), and \(C(2, 0)\).
Figure for problem 534055

Hints

- Use an even quartic model with only even powers. - The y-intercept determines the constant term. - Substitute the other two points to form a system.

Solution

1. Since \(f\) is an even fourth-degree polynomial, write \(f(x)=ax^4+bx^2+c\). 2. Point \(A(0, 2)\) gives \(c=2\). 3. Point \(B(1, 0)\) gives \(a+b+2=0\), so \(a+b=-2\). 4. Point \(C(2, 0)\) gives \(16a+4b+2=0\), so \(16a+4b=-2\). 5. Substituting \(b=-2-a\) gives \(16a+4(-2-a)=-2\), so \(12a=6\) and \(a=0.5\). Then \(b=-2.5\). 6. Therefore, \(f(x)=0.5x^4-2.5x^2+2\).

Answer

\(f(x)=0.5x^4-2.5x^2+2\)
53405611
The graph shown is an odd cubic polynomial \(g\). Find its rule using the points \(P(1, -3)\) and \(Q(2, 0)\).
Figure for problem 534056

Hints

- Use a cubic model containing only odd powers. - Substitute both given points. - Solve the resulting two-equation system.

Solution

1. An odd cubic polynomial has the form \(g(x)=ax^3+bx\). 2. Point \(Q(2, 0)\) gives \(8a+2b=0\), or \(4a+b=0\). 3. Point \(P(1, -3)\) gives \(a+b=-3\). 4. Subtracting the second equation from the first gives \(3a=3\), so \(a=1\). Then \(b=-4\). 5. Therefore, \(g(x)=x^3-4x\).

Answer

\(g(x)=x^3-4x\)
53432311
Consider \(g(x)=x^3-3x\). Give three different reasons, using features such as symmetry, intercepts, or end behavior, why the displayed graph cannot be the graph of \(g\).
Figure for problem 534323

Hints

- Determine whether \(g\) is even or odd. - Evaluate \(g(0)\). - Factor the polynomial to find its zeros. - Compare each algebraic feature with the picture.

Solution

1. The function \(g\) contains only odd powers, so it is odd and its graph must be symmetric about the origin. The displayed graph is not. 2. \(g(0)=0\), so the graph of \(g\) must pass through the origin. The displayed graph has y-intercept \(2\). 3. Factoring gives \(g(x)=x(x^2-3)\), so its real zeros are \(-\sqrt{3}\), \(0\), and \(\sqrt{3}\). The displayed graph instead has zeros at \(-2\) and \(1\), with \(1\) a double zero.

Answer

1. \(g\) is symmetric about the origin, but the displayed graph is not. 2. \(g\) has y-intercept \(0\), but the displayed graph has y-intercept \(2\). 3. \(g\) has real zeros \(-\sqrt{3}, 0, \sqrt{3}\), but the displayed graph has different zeros.
53460211
Match graphs a), b), and c) to the functions below. First classify each function as even, odd, or neither. Then use intercepts, domain, or asymptotic behavior to complete each match. 1) \(f(x)=3e^{-0.5x^2}\) 2) \(g(x)=\frac{x^2-1}{x^2+1}\) 3) \(h(x)=2\ln(x)\)
Figure for problem 534602

Hints

- Check whether each domain is symmetric about zero. - Compare \(f(-x)\) with \(f(x)\) and \(-f(x)\). - Use zeros and asymptotes to distinguish functions with the same symmetry.

Solution

1. The function \(f\) is even because \(f(-x)=f(x)\). Its graph is symmetric about the y-axis, has a maximum at \((0, 3)\), and approaches \(y=0\) as \(x\to\pm\infty\). This matches graph a). 2. The function \(g\) is even because \(g(-x)=g(x)\). It has zeros at \(x=\pm1\) and approaches the horizontal asymptote \(y=1\) as \(|x|\to\infty\). This matches graph b). 3. The function \(h\) is neither even nor odd because its domain is \((0, \infty)\), which is not symmetric about zero. It has a zero at \(x=1\) and a vertical asymptote at \(x=0\). This matches graph c).

Answer

a) \(\rightarrow\) 1), even b) \(\rightarrow\) 2), even c) \(\rightarrow\) 3), neither
53497411
The three panels show the graphs of functions \(f\), \(g\), and \(h\). a) Which function is even? Explain from the graph’s symmetry. b) Which function is odd? c) Why is \(h\) not odd even though its graph has rotational symmetry?
Figure for problem 534974

Hints

- An even graph mirrors across the y-axis. - An odd graph has 180-degree rotational symmetry about the origin. - Identify the actual center of rotational symmetry for \(h\).

Solution

1. The graph of \(f\) is symmetric about the y-axis, so \(f\) is even. 2. The graph of \(g\) is a line through the origin and is symmetric about the origin, so \(g\) is odd. 3. The graph of \(h\) has rotational symmetry about \((0, 2)\), not about the origin. Odd functions must satisfy \(h(-x)=-h(x)\) and, when defined at \(0\), must pass through \((0, 0)\). Therefore, \(h\) is not odd.

Answer

a) \(f\) is even. b) \(g\) is odd. c) \(h\) is symmetric about \((0, 2)\), not about the origin, so it is not odd.
53501511
Consider \(h(x)=\frac{6}{x^2+2}\). a) Find the domain and range of \(h\). b) Use the formula to explain why the graph is symmetric about the y-axis.
Figure for problem 535015

Hints

- Determine whether the denominator can equal zero. - Find the smallest possible denominator and consider what happens as \(|x|\) becomes large. - Compute \(h(-x)\).

Solution

1. Since \(x^2+2\ge2\), the denominator is never zero. Therefore, the domain is \(\mathbb{R}\). 2. The denominator is smallest at \(x=0\), so the maximum output is \(h(0)=3\). The function is always positive, and \(h(x)\to0\) as \(|x|\to\infty\), but it never equals \(0\). Thus, the range is \((0, 3]\). 3. Replace \(x\) with \(-x\): \(h(-x)=\frac{6}{(-x)^2+2}=\frac{6}{x^2+2}=h(x)\). Therefore, \(h\) is even and its graph is symmetric about the y-axis.

Answer

a) Domain: \(\mathbb{R}\); range: \((0, 3]\) b) \(h(-x)=h(x)\), so \(h\) is even.
52181811
A student claims, “If the graphs of \(f\) and \(g\) are reflections of each other across the y-axis, then each graph must also be symmetric about the y-axis.” Evaluate the claim. State the mathematical condition for each type of symmetry and give a counterexample using two functions.

Hints

- Compare an object being symmetric with two different objects being mirror images. - Start with a simple function that is not even, then reflect it across the y-axis. - Write separate equations for the two symmetry relationships.

Solution

1. The claim is false. 2. A single graph is symmetric about the y-axis when its domain is symmetric about \(0\) and \(f(-x)=f(x)\) for every \(x\) in the domain. 3. Two graphs are reflections of each other across the y-axis when their domains are reflected across \(0\) and \(g(x)=f(-x)\). 4. Let \(f(x)=x+1\) and \(g(x)=-x+1\). Since \(f(-x)=-x+1=g(x)\), the graphs are reflections of each other. However, \(f(-x)\ne f(x)\) and \(g(-x)\ne g(x)\) in general, so neither graph is individually symmetric about the y-axis.

Answer

The claim is false. Individual y-axis symmetry requires \(f(-x)=f(x)\). Two graphs are reflections across the y-axis when \(g(x)=f(-x)\), with correspondingly reflected domains. For example, \(f(x)=x+1\) and \(g(x)=-x+1\) are reflections of each other, but neither function is even.
52187611
Evaluate this statement and justify your conclusion: “If a nonzero odd polynomial is shifted vertically by adding a nonzero constant \(c\), the new function is neither odd nor even.”

Hints

- Define the shifted function and test both symmetry identities. - Compare \(g(-x)\) with \(-g(x)\). - For even symmetry, determine what \(-f(x)=f(x)\) would imply.

Solution

1. Let \(f\) be a nonzero odd polynomial, so \(f(-x)=-f(x)\), and define \(g(x)=f(x)+c\) with \(c\ne0\). 2. For odd symmetry, \(g(-x)=-f(x)+c\), while \(-g(x)=-f(x)-c\). These are equal only if \(c=0\), so \(g\) is not odd. 3. For even symmetry, \(g(-x)=g(x)\) would require \(-f(x)+c=f(x)+c\), or \(f(x)=0\) for every \(x\). 4. That would make \(f\) the zero polynomial, contrary to the hypothesis. Therefore, \(g\) is not even. 5. The statement is true.

Answer

The statement is true. A nonzero vertical shift destroys odd symmetry, and the shifted function could be even only if the original odd polynomial were the zero polynomial.
52318211
Let \(f\) be a nonconstant even polynomial function. Determine whether each new function is even, odd, or neither. Justify each answer algebraically. a) \(p(x) = xf(x)\) b) \(q(x) = f(x) + x^2\) c) \(r(x) = f(x + 1)\)

Hints

- Begin with \(f(-x) = f(x)\). - Test the definitions of even and odd functions for parts a) and b). - For part c), remember that a nonconstant even polynomial has even degree. - Consider what the horizontal shift does to the next-highest power in the leading term.

Solution

1. Because \(f\) is even, \(f(-x) = f(x)\). 2. For \(p\), \(p(-x) = (-x)f(-x) = -xf(x) = -p(x)\). Therefore, \(p\) is odd. 3. For \(q\), \(q(-x) = f(-x) + (-x)^2 = f(x) + x^2 = q(x)\). Therefore, \(q\) is even. 4. Since \(f\) is a nonconstant even polynomial, its degree is an even number \(2n\). The translated polynomial \(r(x) = f(x + 1)\) still has even degree, so it cannot be odd. 5. If the leading term of \(f\) is \(ax^{2n}\), then expanding \(a(x + 1)^{2n}\) produces the nonzero odd-power term \(2na x^{2n-1}\). Lower-degree terms cannot cancel it. Therefore, \(r\) is not even. Thus, \(r\) is neither even nor odd.

Answer

a) Odd; the graph is symmetric about the origin. b) Even; the graph is symmetric about the y-axis. c) Neither even nor odd.

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