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Slant asymptotes

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52194112
Consider the rational function \(f(x)=3x+1-\frac{2}{x+4}\). Give the equation of the slant asymptote. Then describe the graph's end behavior as \(x\to\infty\) and as \(x\to-\infty\), including whether the graph approaches the asymptote from above or below.

Hints

- Which part of the function approaches \(0\) as \(|x|\) becomes large? - How does a line with positive slope behave as \(x\to\infty\) and as \(x\to-\infty\)? - Check the sign of the fractional term for large positive and negative values of \(x\).

Solution

1. Since \(\frac{2}{x+4}\to 0\) as \(x\to\pm\infty\), the slant asymptote is \(y=3x+1\). 2. As \(x\to\infty\), \(f(x)\to\infty\). Because \(\frac{2}{x+4}>0\) for large positive \(x\), \(f(x)<3x+1\), so the graph approaches the asymptote from below. 3. As \(x\to-\infty\), \(f(x)\to-\infty\). Because \(\frac{2}{x+4}<0\) for large negative \(x\), \(f(x)>3x+1\), so the graph approaches the asymptote from above.

Answer

The slant asymptote is \(y=3x+1\). As \(x\to\infty\), \(f(x)\to\infty\), and the graph approaches the asymptote from below. As \(x\to-\infty\), \(f(x)\to-\infty\), and the graph approaches the asymptote from above.
53006512
Consider \(f(x)=\frac{3x^2-6x+2}{x-2}\). Find the linear function \(g\) that approximates \(f\) for large \(\lvert x\rvert\). Then determine whether the graph of \(f\) approaches \(g\) from above or below as \(x\to\infty\) and as \(x\to-\infty\).

Hints

- Use polynomial division to separate a linear part and a proper rational remainder. - The sign of \(f(x)-g(x)\) determines the graph's position relative to \(g\). - Check the sign of the remainder term for large positive and large negative values of \(x\).

Solution

1. Polynomial division gives \(f(x)=3x+\frac{2}{x-2}\). 2. The linear approximation, which is also the slant asymptote, is \(g(x)=3x\). 3. The difference is \(f(x)-g(x)=\frac{2}{x-2}\). 4. As \(x\to\infty\), the difference is positive, so the graph approaches \(g\) from above. 5. As \(x\to-\infty\), the difference is negative, so the graph approaches \(g\) from below.

Answer

\(g(x)=3x\) As \(x\to\infty\), the graph approaches from above. As \(x\to-\infty\), the graph approaches from below.
51011012
The graph of \(f(x)=\frac{x^3-1}{(x+1)(x-2)}\) has three asymptotes. Which equation is not one of them? a) \(y=x+1\) b) \(x=-1\) c) \(x=1\) d) \(x=2\)

Hints

- Denominator zeros may produce vertical asymptotes. - Compare the degrees of the numerator and denominator. - Use polynomial division to separate the function into a polynomial part and a remainder term. - Decide which choices describe vertical or end-behavior asymptotes. - Check whether any listed value is instead a zero of the numerator. - Can an x-intercept be a vertical asymptote at the same defined point?

Solution

1. The denominator is zero at \(x=-1\) and \(x=2\). The numerator is nonzero at both values, so \(x=-1\) and \(x=2\) are vertical asymptotes. 2. The degree of the numerator is one greater than the degree of the denominator, so the graph has a slant asymptote. 3. Divide \(x^3-1\) by \(x^2-x-2\): \(\frac{x^3-1}{x^2-x-2}=x+1+\frac{3x+1}{x^2-x-2}\). 4. The remainder term approaches \(0\) as \(|x|\to\infty\), so the slant asymptote is \(y=x+1\). 5. Therefore, \(x=1\) is not an asymptote. It is the x-coordinate of an x-intercept.

Answer

c) \(x=1\)
52191812
Find the equations of all asymptotes of \(h(x)=\frac{2x^2+5x-1}{x+2}\).

Hints

- First find where the function is undefined. - Compare the degrees of the numerator and denominator. - Use polynomial division to separate a linear part from a proper rational remainder. - Which term approaches zero as \(|x|\to\infty\)?

Solution

1. The denominator is zero at \(x=-2\). The numerator there is \(2(-2)^2+5(-2)-1=-3\neq 0\), so the vertical asymptote is \(x=-2\). 2. The numerator’s degree is one greater than the denominator’s degree, so use polynomial division. 3. Dividing gives \(2x^2+5x-1=(x+2)(2x+1)-3\). 4. Therefore, \(h(x)=2x+1-\frac{3}{x+2}\). 5. Since \(-\frac{3}{x+2}\to 0\) as \(|x|\to\infty\), the slant asymptote is \(y=2x+1\).

Answer

Vertical asymptote: \(x=-2\) Slant asymptote: \(y=2x+1\)
52193812
Let \(f(x)=\frac{2x^2+5x}{x+1}\), with domain \(\mathbb{R}\setminus\{-1\}\). A student predicts that for large positive values of \(x\), the graph behaves approximately like the line \(y=2x+3\). Determine whether the prediction is correct.

Hints

- Use polynomial division to separate a linear expression and a proper rational remainder. - What happens to the remainder term as \(x\to\infty\)? - The quotient from polynomial division determines the slant asymptote.

Solution

1. Use polynomial division: \(\frac{2x^2+5x}{x+1}=2x+3-\frac{3}{x+1}\). 2. As \(x\to\infty\), the remainder term \(-\frac{3}{x+1}\to 0\). 3. Therefore, the difference between \(f(x)\) and \(2x+3\) approaches \(0\). 4. The prediction is correct, and the slant asymptote is \(y=2x+3\).

Answer

The prediction is correct. Since \(f(x)=2x+3-\frac{3}{x+1}\) and the remainder term approaches \(0\), the slant asymptote is \(y=2x+3\).
52193912
Analyze the end behavior of each function as \(x\to\infty\) and \(x\to-\infty\). State whether the function approaches a finite value or is unbounded, and give the equation of its horizontal or slant asymptote. a) \(f(x)=\frac{10x^2-5}{2x^2+3x}\) b) \(g(x)=\frac{x^2+2x-1}{x+1}\) c) \(h(x)=\frac{1-4x}{2x+8}\)

Hints

- Compare the degrees of the numerator and denominator. - When the degrees are equal, use the ratio of leading coefficients. - When the numerator’s degree is one greater, use polynomial division. - The remainder term determines how the graph approaches the polynomial quotient.

Solution

1. For part a, the numerator and denominator have the same degree. The ratio of leading coefficients is \(\frac{10}{2}=5\), so \(f(x)\to 5\) as \(x\to\pm\infty\). The horizontal asymptote is \(y=5\). 2. For part b, polynomial division gives \(g(x)=x+1-\frac{2}{x+1}\). The function is unbounded as \(x\to\pm\infty\), but the difference between \(g(x)\) and \(x+1\) approaches \(0\). The slant asymptote is \(y=x+1\). 3. For part c, the numerator and denominator have the same degree. The ratio of leading coefficients is \(\frac{-4}{2}=-2\), so \(h(x)\to-2\) as \(x\to\pm\infty\). The horizontal asymptote is \(y=-2\).

Answer

a) Approaches \(5\); horizontal asymptote \(y=5\) b) Is unbounded; slant asymptote \(y=x+1\) c) Approaches \(-2\); horizontal asymptote \(y=-2\)
52195412
Consider the rational function \(k(x)=\frac{2x^2-5x+1}{x-2}\). Use polynomial division to determine the end behavior of \(k\) as \(x\to\infty\) and as \(x\to-\infty\). Give the equation of the slant asymptote.

Hints

- When the numerator's degree is exactly one greater than the denominator's degree, polynomial division can reveal a slant asymptote. - Separate the expression into a linear quotient and a proper rational remainder. - What happens to the remainder term as \(|x|\) becomes large?

Solution

1. Divide \(2x^2-5x+1\) by \(x-2\). 2. The first quotient term is \(2x\). Subtracting \(2x(x-2)=2x^2-4x\) leaves \(-x+1\). 3. The next quotient term is \(-1\). Subtracting \(-(x-2)=-x+2\) leaves a remainder of \(-1\). 4. Therefore, \(k(x)=2x-1-\frac{1}{x-2}\). 5. Since \(-\frac{1}{x-2}\to 0\) as \(x\to\pm\infty\), the graph approaches \(y=2x-1\).

Answer

\(k(x)=2x-1-\frac{1}{x-2}\). As \(x\to\pm\infty\), the graph approaches the slant asymptote \(y=2x-1\).
52195612
Consider \(g(x)=\frac{-x^2+6x+4}{x}\), where \(x\neq 0\). a) Rewrite the function as a sum and determine the equation of its slant asymptote. b) Determine algebraically whether the graph of \(g\) intersects its slant asymptote.

Hints

- Divide each term in the numerator by \(x\). - To find intersections of two graphs, set their equations equal. - Can a fraction with a nonzero constant numerator equal \(0\)?

Solution

1. Divide each term in the numerator by \(x\): \(g(x)=-x+6+\frac{4}{x}\). 2. Since \(\frac{4}{x}\to 0\) as \(x\to\pm\infty\), the slant asymptote is \(y=-x+6\). 3. To check for an intersection, solve \(-x+6+\frac{4}{x}=-x+6\). 4. This simplifies to \(\frac{4}{x}=0\), which has no solution. 5. Therefore, the graph does not intersect its slant asymptote.

Answer

a) \(g(x)=-x+6+\frac{4}{x}\); slant asymptote: \(y=-x+6\) b) The graph does not intersect the asymptote because \(\frac{4}{x}=0\) has no solution.
52195712
Consider the rational function \(f(x)=\frac{x^2-4x+5}{x-3}\). 1) Find the equation of the slant asymptote. 2) As \(x\to\infty\), determine whether the graph lies above or below the slant asymptote. Explain your reasoning.

Hints

- Use polynomial division to write the function as a linear expression plus a remainder term. - The linear expression gives the slant asymptote. - Determine the sign of the remainder term for large positive \(x\).

Solution

1. Polynomial division gives \(f(x)=x-1+\frac{2}{x-3}\). 2. Therefore, the slant asymptote is \(y=x-1\). 3. For sufficiently large positive \(x\), \(x-3>0\), so \(\frac{2}{x-3}>0\). 4. Thus, \(f(x)>x-1\), and the graph approaches the asymptote from above as \(x\to\infty\).

Answer

1) The slant asymptote is \(y=x-1\). 2) The graph lies above the asymptote for large positive \(x\) because \(\frac{2}{x-3}>0\).
52195812
A student analyzes \(g(x)=\frac{-2x^2+3}{x+1}\) and makes this claim: “Because the numerator's degree is one greater than the denominator's degree, the function has a slant asymptote. Comparing the leading coefficients gives the asymptote \(y=-2x\).” Check the claim using polynomial division. Explain why the student's reasoning is incomplete, and give the correct equation of the slant asymptote.

Hints

- Complete the polynomial division rather than comparing only the leading terms. - A line \(y=mx+b\) requires both a slope and a y-intercept. - Identify which part of the quotient the leading-coefficient comparison determines.

Solution

1. Divide \(-2x^2+3\) by \(x+1\): \(g(x)=-2x+2+\frac{1}{x+1}\). 2. The ratio of leading coefficients correctly gives the slope \(-2\), but it does not determine the constant term of the asymptote. 3. Since \(\frac{1}{x+1}\to 0\) as \(x\to\pm\infty\), the correct slant asymptote is \(y=-2x+2\).

Answer

The claim is incorrect. Polynomial division gives \(g(x)=-2x+2+\frac{1}{x+1}\). Comparing leading coefficients gives only the slope; the student omitted the constant term \(2\). The slant asymptote is \(y=-2x+2\).
52199112
Find a rational function \(f\) whose slant asymptote is \(y=2x-4\), whose vertical asymptote is \(x=3\), and whose graph passes through \(P=(4, 6)\).

Hints

- Write the function as the slant-asymptote expression plus a term that approaches zero. - Use a denominator factor to create the vertical asymptote. - Substitute the given point to determine the unknown constant.

Solution

1. Use the form \(f(x)=2x-4+\frac{a}{x-3}\). The rational term approaches \(0\) as \(|x|\to\infty\) and creates a vertical asymptote at \(x=3\). 2. Substitute \(P=(4, 6)\): \(6=2\cdot 4-4+\frac{a}{4-3}=4+a\). 3. Therefore, \(a=2\), so \(f(x)=2x-4+\frac{2}{x-3}\).

Answer

\(f(x)=2x-4+\frac{2}{x-3}\)
52202212
Consider \(h(x)=\frac{x^2-4x+7}{x-4}\), where \(x\neq 4\). Find the equation of the slant asymptote. Prove that the graph of \(h\) and its slant asymptote have no points in common, and describe what this means for the graph's position relative to the asymptote.

Hints

- Use polynomial division or rewrite the numerator in terms of \(x-4\). - Set the function equal to its asymptote to test for intersections. - Examine the sign of the remainder term on each side of \(x=4\).

Solution

1. Rewrite the function as \(h(x)=x+\frac{7}{x-4}\). 2. Since \(\frac{7}{x-4}\to 0\) as \(x\to\pm\infty\), the slant asymptote is \(y=x\). 3. To find an intersection, solve \(x+\frac{7}{x-4}=x\). This reduces to \(\frac{7}{x-4}=0\), which has no solution. 4. For \(x>4\), \(\frac{7}{x-4}>0\), so the graph lies above \(y=x\). For \(x<4\), \(\frac{7}{x-4}<0\), so the graph lies below \(y=x\).

Answer

The slant asymptote is \(y=x\). The equation \(\frac{7}{x-4}=0\) has no solution, so the graph never intersects the asymptote. It lies above the asymptote for \(x>4\) and below it for \(x<4\).
52204412
Consider the functions \(g_1(x)=x-2+\frac{5}{x+3}\), \(g_2(x)=\frac{x^2-2x+1}{x}\), \(g_3(x)=\frac{2x^2-4x+3}{2x}\), and \(g_4(x)=\frac{x^2+1}{x+2}\). Show algebraically that all four graphs have the same slant asymptote. Give its equation.

Hints

- Rewrite each function as a linear expression plus a proper rational remainder. - Use term-by-term division when the denominator is a monomial. - Use polynomial division when necessary. - Which part remains after the term that approaches \(0\) is removed?

Solution

1. The function \(g_1\) is already written as \(x-2\) plus a term that approaches \(0\), so its slant asymptote is \(y=x-2\). 2. Divide term by term: \(g_2(x)=x-2+\frac{1}{x}\). The remainder term approaches \(0\), so the asymptote is \(y=x-2\). 3. Similarly, \(g_3(x)=x-2+\frac{3}{2x}\). The remainder term approaches \(0\), so the asymptote is \(y=x-2\). 4. Polynomial division gives \(g_4(x)=x-2+\frac{5}{x+2}\). The remainder term approaches \(0\), so the asymptote is \(y=x-2\). 5. Therefore, all four graphs have the same slant asymptote.

Answer

All four functions have the slant asymptote \(y=x-2\).
52204512
Consider \(f(x)=\frac{1}{2}x-1-\frac{4}{x+3}\). a) Find the domain and the equation of the vertical asymptote. b) Describe the end behavior as \(x\to\infty\) and as \(x\to-\infty\). Give the equation of the slant asymptote. c) Determine algebraically whether the graph intersects its slant asymptote.

Hints

- Which value makes the denominator equal to \(0\)? - What happens to the rational remainder as \(|x|\) becomes large? - To test for an intersection, set the function equal to the asymptote.

Solution

1. The denominator requires \(x+3\neq 0\), so the domain is \(\mathbb{R}\setminus\{-3\}\). The vertical asymptote is \(x=-3\). 2. Since \(-\frac{4}{x+3}\to 0\) as \(x\to\pm\infty\), the graph approaches \(y=\frac{1}{2}x-1\). 3. Thus, \(f(x)\to\infty\) as \(x\to\infty\), and \(f(x)\to-\infty\) as \(x\to-\infty\). The slant asymptote is \(y=\frac{1}{2}x-1\). 4. Setting the function equal to the asymptote gives \(-\frac{4}{x+3}=0\), which has no solution. Therefore, the graph does not intersect the slant asymptote.

Answer

a) Domain: \(\mathbb{R}\setminus\{-3\}\); vertical asymptote: \(x=-3\) b) \(f(x)\to\infty\) as \(x\to\infty\), and \(f(x)\to-\infty\) as \(x\to-\infty\); slant asymptote: \(y=\frac{1}{2}x-1\) c) The graph does not intersect the slant asymptote.
52205212
A rational function has the form \(k(x)=\frac{a}{x-b}+c\). Its vertical asymptote is \(x=2\), its horizontal asymptote is \(y=3\), and its graph passes through \(P=(3, 5)\). a) Find \(a\), \(b\), and \(c\). b) Find the zero of \(k\). c) Define \(m(x)=k(x)-3x\). Find all asymptotes of \(m\).

Hints

- Use the asymptotes to identify \(b\) and \(c\). - Substitute the given point to find \(a\). - Set the full function equal to zero. - Rewrite \(m\) as a linear expression plus a rational term that approaches zero.

Solution

1. The vertical asymptote gives \(b=2\), and the horizontal asymptote gives \(c=3\). 2. Substitute \(P=(3, 5)\): \(5=\frac{a}{3-2}+3\), so \(a=2\). Thus, \(k(x)=\frac{2}{x-2}+3\). 3. To find the zero, solve \(\frac{2}{x-2}+3=0\). Then \(2=-3(x-2)\), so \(3x=4\) and \(x=\frac{4}{3}\). 4. \(m(x)=\frac{2}{x-2}+3-3x=-3x+3+\frac{2}{x-2}\). 5. The vertical asymptote remains \(x=2\). Since \(\frac{2}{x-2}\to0\) as \(|x|\to\infty\), the slant asymptote is \(y=-3x+3\).

Answer

a) \(a=2\), \(b=2\), \(c=3\) b) \(x=\frac{4}{3}\) c) Vertical asymptote: \(x=2\); slant asymptote: \(y=-3x+3\)
52205412
Consider \(k(x)=\frac{0.5x^2+2x-1}{x-2}\). 1) Determine the end behavior of \(k(x)\) as \(x\to\infty\) and as \(x\to-\infty\). 2) Use polynomial division to find the equation of the slant asymptote.

Hints

- The numerator's degree is one greater than the denominator's degree. - Use polynomial division to separate a linear quotient from a proper rational remainder. - What happens to the remainder term as \(|x|\) becomes large?

Solution

1. Divide \(0.5x^2+2x-1\) by \(x-2\): \(k(x)=0.5x+3+\frac{5}{x-2}\). 2. Since \(\frac{5}{x-2}\to 0\) as \(x\to\pm\infty\), the graph approaches \(y=0.5x+3\). 3. Therefore, \(k(x)\to\infty\) as \(x\to\infty\), and \(k(x)\to-\infty\) as \(x\to-\infty\).

Answer

1) \(k(x)\to\infty\) as \(x\to\infty\), and \(k(x)\to-\infty\) as \(x\to-\infty\) 2) Slant asymptote: \(y=0.5x+3\)
52287712
Consider \(f(x)=\frac{x^2-3x}{x-2}\). a) Find the domain of \(f\). b) Find the equations of the vertical asymptote and the slant asymptote. c) Find \(f(4)\).

Hints

- A rational function is undefined where its denominator is \(0\). - Check whether the excluded factor cancels before identifying a vertical asymptote. - Use polynomial division to find a slant asymptote. - Substitute \(x=4\) to evaluate the function.

Solution

1. The denominator is zero at \(x=2\), so the domain is \(\mathbb{R}\setminus\{2\}\). 2. The numerator is \(-2\) at \(x=2\), so the factor does not cancel. Therefore, the vertical asymptote is \(x=2\). 3. Polynomial division gives \(f(x)=x-1-\frac{2}{x-2}\). Since the remainder term approaches \(0\), the slant asymptote is \(y=x-1\). 4. Evaluate \(f(4)=\frac{4^2-3\cdot 4}{4-2}=\frac{4}{2}=2\).

Answer

a) \(\mathbb{R}\setminus\{2\}\) b) Vertical asymptote: \(x=2\); slant asymptote: \(y=x-1\) c) \(f(4)=2\)
53004812
Consider \(g(x)=\frac{2x^2+3x-4}{x}\). 1) Rewrite the function as the sum of a linear expression and a proper rational expression. 2) Determine the end behavior of \(g(x)\) as \(x\to\infty\) and as \(x\to-\infty\). 3) As \(x\to\infty\), determine whether the graph lies above or below its slant asymptote. Justify your answer from the rewritten function.

Hints

- Divide each term in the numerator by \(x\). - Which term determines the overall end behavior, and which term approaches \(0\)? - Compare \(g(x)\) directly with the linear part by checking the sign of their difference.

Solution

1. Divide each term in the numerator by \(x\): \(g(x)=2x+3-\frac{4}{x}\). 2. Since \(-\frac{4}{x}\to 0\), the slant asymptote is \(y=2x+3\). Therefore, \(g(x)\to\infty\) as \(x\to\infty\), and \(g(x)\to-\infty\) as \(x\to-\infty\). 3. For positive \(x\), \(-\frac{4}{x}<0\). Thus, \(g(x)<2x+3\), so the graph approaches the asymptote from below as \(x\to\infty\).

Answer

1) \(g(x)=2x+3-\frac{4}{x}\) 2) \(g(x)\to\infty\) as \(x\to\infty\), and \(g(x)\to-\infty\) as \(x\to-\infty\) 3) The graph lies below the slant asymptote \(y=2x+3\) for large positive \(x\).
53005312
Consider \(f(x)=\frac{x^2+2x-5}{x+3}\). 1) Use polynomial division to write \(f(x)=p(x)+\frac{c}{x+3}\), where \(p\) is linear and \(c\) is a constant. 2) Give the equation of the slant asymptote. 3) Use the remainder term to determine whether the graph approaches the asymptote from above or below as \(x\to\infty\).

Hints

- Use polynomial division to separate a linear quotient and a remainder term. - Which part approaches \(0\) as \(x\to\infty\)? - The sign of the remainder term determines whether the graph is above or below the asymptote.

Solution

1. Polynomial division gives \(f(x)=x-1-\frac{2}{x+3}\). 2. Since \(-\frac{2}{x+3}\to 0\) as \(x\to\pm\infty\), the slant asymptote is \(y=x-1\). 3. For large positive \(x\), \(-\frac{2}{x+3}<0\). Therefore, \(f(x)<x-1\), so the graph approaches the asymptote from below.

Answer

1) \(f(x)=x-1-\frac{2}{x+3}\) 2) \(y=x-1\) 3) The graph approaches the asymptote from below as \(x\to\infty\).
53006312
Consider \(f(x)=\frac{3x^2+x-2}{x+2}\). 1) Find the equation of the slant asymptote \(a\). 2) Find all values of \(x\) for which the function value differs from the corresponding value of the asymptote by less than \(0.4\).

Hints

- Use polynomial division to identify the linear part and the remainder term. - The vertical distance from the function to the asymptote is the absolute value of the remainder term. - Solve the resulting absolute-value inequality carefully.

Solution

1. Polynomial division gives \(f(x)=3x-5+\frac{8}{x+2}\). Therefore, the slant asymptote is \(a(x)=3x-5\). 2. The required condition is \(\lvert f(x)-a(x)\rvert<0.4\), so \(\left\lvert\frac{8}{x+2}\right\rvert<0.4\). 3. This is equivalent to \(\frac{8}{\lvert x+2\rvert}<0.4\), which gives \(\lvert x+2\rvert>20\). 4. Therefore, \(x+2>20\) or \(x+2<-20\), so \(x>18\) or \(x<-22\).

Answer

1) \(a(x)=3x-5\) 2) \(x\in(-\infty, -22)\cup(18, \infty)\)
53008512
Decide whether each statement about a rational function \(f(x)=\frac{p(x)}{q(x)}\) is true or false. Briefly justify each answer. a) If the degree of \(p\) is exactly one greater than the degree of \(q\), the graph has a slant asymptote. b) A rational function whose graph is symmetric about the origin can have \(y=2\) as a horizontal asymptote. c) If \(p\) contains only even powers of \(x\) and \(q\) contains only odd powers of \(x\), the graph of \(f\) is symmetric about the origin.

Hints

- Use polynomial division when the numerator degree is one greater. - Combine the origin-symmetry condition with the two end limits. - Recall how even and odd functions behave when evaluated at \(-x\).

Solution

1. a) True. Polynomial division produces a nonconstant linear quotient plus a remainder term whose ratio to \(q(x)\) approaches \(0\). The linear quotient is the slant asymptote. 2. b) False. Origin symmetry means \(f(-x)=-f(x)\). If both end limits are the same finite number \(L\), this symmetry requires \(L=-L\), so \(L=0\). Therefore, \(y=2\) cannot be the horizontal asymptote. 3. c) True. A polynomial with only even powers is even, so \(p(-x)=p(x)\). A polynomial with only odd powers is odd, so \(q(-x)=-q(x)\). Hence \(f(-x)=\frac{p(x)}{-q(x)}=-f(x)\) wherever the function is defined.

Answer

a) True b) False c) True
53015412
Find one rational function \(g\) that is defined for every real number, has slant asymptote \(y=-x+1\), and has y-intercept \((0, 2)\).

Hints

- Choose a denominator that is never zero. - Start with the slant-asymptote expression and add a term that approaches zero. - Use the y-intercept to determine the numerator of the remainder term. - The expression \(x^2+1\) is positive for every real \(x\).

Solution

1. To make the function defined for every real number, use a denominator with no real zeros, such as \(x^2+1\). 2. Write \(g(x)=-x+1+\frac{a}{x^2+1}\). The rational term approaches \(0\) as \(|x|\to\infty\), so the slant asymptote is \(y=-x+1\). 3. Use the y-intercept: \(2=g(0)=1+a\), so \(a=1\). 4. Therefore, \(g(x)=-x+1+\frac{1}{x^2+1}\). As one fraction, \(g(x)=\frac{-x^3+x^2-x+2}{x^2+1}\).

Answer

One possible formula is \(g(x)=-x+1+\frac{1}{x^2+1}\).
53363912
The graph of \(f(x)=0.5x+\frac{2}{x}\) is shown. Find the equations of the vertical asymptote and the slant asymptote. Explain how each can be identified directly from the function's equation.
Figure for problem 533639

Hints

- At which value is the rational term undefined? - What happens to \(\frac{2}{x}\) as \(\lvert x\rvert\) becomes large? - The remaining linear term determines the slant asymptote.

Solution

1. The term \(\frac{2}{x}\) is undefined at \(x=0\), and its magnitude becomes unbounded as \(x\to 0\). Therefore, the vertical asymptote is \(x=0\). 2. As \(x\to\pm\infty\), \(\frac{2}{x}\to 0\). Therefore, \(f(x)\) approaches \(0.5x\), so the slant asymptote is \(y=0.5x\).

Answer

Vertical asymptote: \(x=0\) Slant asymptote: \(y=0.5x\)
53410112
Find one possible rational function \(f\) whose graph has all three features. 1. It approaches the line \(y=2x-3\) as \(x\to\pm\infty\). 2. It has a vertical asymptote at \(x=2\). 3. It passes through \(P=(1, 0)\).
Figure for problem 534101

Hints

- Write the function as the slant-asymptote expression plus a rational remainder. - Use the denominator to create the vertical asymptote. - Substitute the given point to find the unknown constant.

Solution

1. Use the form \(f(x)=2x-3+\frac{k}{x-2}\). 2. Substitute \(P=(1, 0)\): \(0=2\cdot 1-3+\frac{k}{1-2}=-1-k\). Therefore, \(k=-1\). 3. One possible function is \(f(x)=2x-3-\frac{1}{x-2}\). 4. As one fraction, \(f(x)=\frac{(2x-3)(x-2)-1}{x-2}=\frac{2x^2-7x+5}{x-2}\).

Answer

One possible formula is \(f(x)=2x-3-\frac{1}{x-2}\).
53441312
The graph of \(f\) has a slant asymptote. Find the equation of the asymptote and one possible function rule for \(f\).
Figure for problem 534413

Hints

- Find the slope and intercept of the dashed line. - Use the vertical asymptote to choose the denominator of the remainder term. - Substitute a clear point such as \((1, 3)\) to determine the remaining constant.

Solution

1. The dashed line passes through the origin with slope \(1\), so the slant asymptote is \(y=x\). 2. The graph has a vertical asymptote at \(x=0\), so use \(f(x)=x+\frac{k}{x}\). 3. The graph passes through \((1, 3)\). Substituting gives \(3=1+k\), so \(k=2\). 4. Therefore, one possible function is \(f(x)=x+\frac{2}{x}\).

Answer

Slant asymptote: \(y=x\); one possible function: \(f(x)=x+\frac{2}{x}\)
52195012
Consider the functions \(f(x)=\frac{1-4x}{2x+6}\), \(g(x)=\frac{x^2+1}{x-1}\), and \(h(x)=\frac{3x-2}{x^2+2}\). Determine whether each statement is true or false. Justify your answers. a) The x-axis is a horizontal asymptote of the graph of \(h\). b) The graph of \(g\) has the slant asymptote \(y=x+1\). c) The graphs of \(f\) and \(h\) have the same total number of horizontal, slant, and vertical asymptotes. d) As \(x\to\infty\), all three functions have the same limiting behavior.

Hints

- Analyze each function separately. - Check excluded values when looking for vertical asymptotes. - Use polynomial division when the numerator's degree is one greater than the denominator's degree. - Compare the leading terms to determine end behavior.

Solution

1. For \(h\), the denominator has greater degree than the numerator, so \(h(x)\to 0\) as \(x\to\infty\). Thus, a) is true. 2. Polynomial division gives \(g(x)=x+1+\frac{2}{x-1}\). Therefore, \(y=x+1\) is the slant asymptote, so b) is true. 3. The graph of \(f\) has a vertical asymptote at \(x=-3\) and a horizontal asymptote at \(y=-2\), for a total of two. Since \(x^2+2>0\) for all real \(x\), \(h\) has no vertical asymptote and has only the horizontal asymptote \(y=0\). Therefore, c) is false. 4. As \(x\to\infty\), \(f(x)\to-2\), \(g(x)\to\infty\), and \(h(x)\to 0\). Therefore, d) is false.

Answer

a) True b) True c) False; \(f\) has two asymptotes, while \(h\) has one. d) False; as \(x\to\infty\), \(f(x)\to-2\), \(g(x)\to\infty\), and \(h(x)\to 0\).
52199612
Find one rational function \(g\) whose graph has all three features. - It is symmetric about the origin. - Its vertical asymptotes are \(x=-2\) and \(x=2\). - Its slant asymptote is \(y=x\).

Hints

- Symmetry about the origin requires \(g(-x)=-g(x)\). - Use denominator factors for the two vertical asymptotes. - Use polynomial division to control the slant asymptote. - Choose an odd numerator and an even denominator.

Solution

1. The vertical asymptotes suggest the denominator \((x-2)(x+2)=x^2-4\). 2. Symmetry about the origin requires an odd function. Since the denominator is even, choose an odd numerator. 3. A slant asymptote \(y=x\) requires the numerator degree to be one greater than the denominator degree and the quotient from polynomial division to be \(x\). 4. Choose \(g(x)=\frac{x^3}{x^2-4}\). Polynomial division gives \(g(x)=x+\frac{4x}{x^2-4}\), so the slant asymptote is \(y=x\). Also, \(g(-x)=-g(x)\), and the numerator is nonzero at \(x=\pm2\).

Answer

One possible formula is \(g(x)=\frac{x^3}{x^2-4}\).
52953212
Consider \(f(x)=\sqrt{4x^2+4x+10}\). 1. Find the location and type of the extremum. 2. The second derivative is \(f^{\prime\prime}(x)=\frac{36}{(4x^2+4x+10)^{3/2}}\). Explain why \(f\) has no inflection points. 3. Find \(\lim_{x\to\infty}f^{\prime}(x)\) and \(\lim_{x\to-\infty}f^{\prime}(x)\). 4. Use the end behavior to find the two slant asymptotes of the graph.

Hints

- Use the sign of the given second derivative to classify the critical point. - Remember that \(\sqrt{x^2}=|x|\) when evaluating limits at infinity. - Complete the square inside the radical to identify the intercepts of the slant asymptotes.

Solution

1. The first derivative is \(f^{\prime}(x)=\frac{4x+2}{\sqrt{4x^2+4x+10}}\). Setting the numerator equal to zero gives \(x=-\frac{1}{2}\). Since \(f(-\frac{1}{2})=3\) and \(f^{\prime\prime}(x)>0\), the graph has a local and absolute minimum at \((-\frac{1}{2}, 3)\). 2. The expression \(4x^2+4x+10\) is positive for every real \(x\), so \(f^{\prime\prime}(x)>0\) everywhere. The concavity never changes, so there are no inflection points. 3. Divide numerator and denominator of \(f^{\prime}\) by \(|x|\). For \(x\to\infty\), the limit is \(2\); for \(x\to-\infty\), the limit is \(-2\). 4. Complete the square: \(f(x)=\sqrt{(2x+1)^2+9}\). As \(x\to\infty\), \(f(x)-(2x+1)\to0\), so one asymptote is \(y=2x+1\). As \(x\to-\infty\), \(f(x)-(-2x-1)\to0\), so the other is \(y=-2x-1\).

Answer

1. Absolute minimum at \((-\frac{1}{2}, 3)\) 2. \(f^{\prime\prime}(x)>0\) for all \(x\), so there are no inflection points. 3. \(\lim_{x\to\infty}f^{\prime}(x)=2\) and \(\lim_{x\to-\infty}f^{\prime}(x)=-2\) 4. \(y=2x+1\) and \(y=-2x-1\)
53004912
Find one rational function \(f\) that has a vertical asymptote at \(x=4\), with the same sign on both sides, and has slant asymptote \(y=2x-1\).

Hints

- Use an even denominator multiplicity to avoid a sign change. - Write the function as the slant-asymptote expression plus a rational term that approaches zero. - Make sure the added rational term is nonzero near \(x=4\). - You may leave the answer in sum form or combine it into one fraction.

Solution

1. A vertical asymptote at \(x=4\) without a sign change can be created with the squared denominator factor \((x-4)^2\). 2. Write the function as its slant asymptote plus a proper rational term: \(f(x)=2x-1+\frac{k}{(x-4)^2}\), where \(k\ne0\). 3. Choose \(k=1\). Then \(f(x)=2x-1+\frac{1}{(x-4)^2}\). 4. As one fraction, \(f(x)=\frac{(2x-1)(x-4)^2+1}{(x-4)^2}=\frac{2x^3-17x^2+40x-15}{x^2-8x+16}\). 5. The rational remainder approaches \(0\) as \(|x|\to\infty\), and the numerator is \(1\) at \(x=4\), so the required asymptotes remain.

Answer

One possible formula is \(f(x)=2x-1+\frac{1}{(x-4)^2}\).
53005412
Consider \(g(x)=\frac{2x^3-x^2+2x+1}{x^2+2}\). Use polynomial division to find the equation of the slant asymptote. Then determine algebraically whether the graph intersects the asymptote and, if it does, give the coordinates of the intersection.

Hints

- In polynomial division, the remainder must have lower degree than the divisor. - The graph meets the asymptote when the remainder term equals \(0\). - When is a rational expression equal to \(0\)?

Solution

1. Polynomial division gives \(g(x)=2x-1+\frac{-2x+3}{x^2+2}\). 2. Since the remainder term approaches \(0\) as \(x\to\pm\infty\), the slant asymptote is \(y=2x-1\). 3. The graph intersects the asymptote when \(\frac{-2x+3}{x^2+2}=0\). Because \(x^2+2>0\), solve \(-2x+3=0\), giving \(x=\frac{3}{2}\). 4. Substitute into the asymptote: \(y=2\cdot\frac{3}{2}-1=2\). The intersection is \(\left(\frac{3}{2}, 2\right)\).

Answer

Slant asymptote: \(y=2x-1\) Intersection: \(\left(\frac{3}{2}, 2\right)\)
53006012
Find the vertical asymptotes and the slant asymptote for each function. a) \(g(x)=\frac{x^2+3}{x+1}\) b) \(g(x)=\frac{1}{3}x-\frac{2x}{x-2}\)

Hints

- Find values that make the denominator equal to \(0\). - Use polynomial division to separate a linear part and a remainder. - In part b), rewrite the rational term before combining it with the linear term.

Solution

1. For a), the denominator is zero at \(x=-1\), and the numerator is nonzero there, so the vertical asymptote is \(x=-1\). Polynomial division gives \(g(x)=x-1+\frac{4}{x+1}\), so the slant asymptote is \(y=x-1\). 2. For b), the denominator is zero at \(x=2\), and the numerator of the fractional term is nonzero there, so the vertical asymptote is \(x=2\). Rewrite \(\frac{2x}{x-2}=2+\frac{4}{x-2}\). Then \(g(x)=\frac{1}{3}x-2-\frac{4}{x-2}\), so the slant asymptote is \(y=\frac{1}{3}x-2\).

Answer

a) Vertical asymptote: \(x=-1\); slant asymptote: \(y=x-1\) b) Vertical asymptote: \(x=2\); slant asymptote: \(y=\frac{1}{3}x-2\)

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