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The points are \(A(3, -2, 1)\) and \(B(7, 2, 3)\).
a) Find \(\overrightarrow{AB}\).
b) Find the distance \(AB\).
c) Give a unit vector in the direction of \(\overrightarrow{AB}\).
Hints
- Subtract the coordinates of \(A\) from those of \(B\).
- Find the vector's magnitude.
- Divide the vector by its magnitude.
Solution
1. \(\overrightarrow{AB}=\begin{pmatrix}4\\4\\2\end{pmatrix}\).
2. Its magnitude is
\(\sqrt{4^2+4^2+2^2}=\sqrt{36}=6\).
3. Divide by the magnitude:
\(\frac{\overrightarrow{AB}}{\|\overrightarrow{AB}\|}
=\frac{1}{6}\begin{pmatrix}4\\4\\2\end{pmatrix}
=\begin{pmatrix}\frac{2}{3}\\\frac{2}{3}\\\frac{1}{3}\end{pmatrix}\).
Answer
a) \(\begin{pmatrix}4\\4\\2\end{pmatrix}\)
b) \(6\)
c) \(\begin{pmatrix}\frac{2}{3}\\\frac{2}{3}\\\frac{1}{3}\end{pmatrix}\)
