Calculus, 10th Edition (Anton)

Published by Wiley
ISBN 10: 0-47064-772-8
ISBN 13: 978-0-47064-772-1

Chapter 11 - Three-Dimensional Space; Vectors - 11.5 Parametric Equations Of Lines - Exercises Set 11.5 - Page 811: 21

Answer

\[ 2 t-2=x, -t=y, \quad 2 t+5=z \]

Work Step by Step

(a) The line in 2d space that passes through the point $P_{0}\left(x_{0}, y_{0}\right)$ and that is parallel to the non-zero vector $\mathbf{v}=\langle a, b\rangle=a \mathbf{i}+b \mathbf{j}$ has parametric equations: \[ a t+x_{0}=x, \quad b t+y_{0}=y \] (b) The line in 3d space that passes through the point $P_{0}\left(x_{0}, y_{0}, z_{0}\right)$ and that is parallel to the non-zero vector $\mathbf{v}=\langle a, b, c\rangle=a \mathbf{i}+b \mathbf{j}+c \mathbf{k}$ has parametric equations \[ a t+x_{0}=x, \quad b t+y_{0}=y, \quad c t+z_{0}=z \] The vector equations for these lines can be written as: \[ \begin{aligned} &\left\langle x_{0}+a t, y_{0}+b t\right\rangle=\langle x, y\rangle \\ &\left\langle x_{0}+a t, y_{0}+b t, z_{0}+c t\right\rangle=\langle x, y, z\rangle \end{aligned} \] or \[ \begin{aligned} &\left\langle x_{0}, y_{0}\right\rangle+t\langle a, b\rangle = \langle x, y\rangle \\ &\left\langle x_{0}, y_{0}, z_{0}\right\rangle+t\langle a, b, c\rangle=\langle x, y, z\rangle \end{aligned} \] Notice that $\langle 2,-1,2\rangle=\vec{v}$ is parallel to the line $2 t+1=x, -t+4=y, z=$ $2 t+6$ So, this vector $\vec{v}=\langle a, b, c\rangle=\langle 2,-1,2\rangle$ is also parallel to the line that passes through $P(-2,0,5)=P\left(x_{0}, y_{0}, z_{0}\right)$ So, the parametric equation of the line can be written as: \[ \begin{aligned} x_{0}+a t=x, y_{0}+b t=y, & z_{0}+c t=z \\ \Rightarrow \quad -2+2 t=x, -t=y, & 5+2 t=z \end{aligned} \]
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.