Calculus 8th Edition

Published by Cengage
ISBN 10: 1285740629
ISBN 13: 978-1-28574-062-1

Chapter 3 - Applications of Differentiation - 3.7 Optimization Problems - 3.7 Exercises - Page 265: 21

Answer

$\left(-\frac{6}{5},\frac{3}{5}\right)$

Work Step by Step

The distance $d$ from the origin $(0,0)$ to a point $(x,2x+3)$ on the line is given by $d$ = $\sqrt {(x-0)^{2}+(2x-3-0)^{2}}$ and the square of the is distance is $S$ = $d^{2}$ = ${(x)^{2}+(2x-3)^{2}}$ $S'(x)$ = $2x+2(2x-3)(2)$ = $10x+12$ $S'(x)$ = $0$ => $x$ = $-\frac{6}{5}$ $S''(x)$ = $10$ $S''(x)$ $\gt$ $0$ so we know that $S$ has a minimum at $x$ = $-\frac{6}{5}$ Thus the y-value is $2\left(-\frac{6}{5}\right)+3$ = $\frac{3}{5}$ and the point is $\left(-\frac{6}{5},\frac{3}{5}\right)$.
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.