Thomas' Calculus 13th Edition

Published by Pearson
ISBN 10: 0-32187-896-5
ISBN 13: 978-0-32187-896-0

Chapter 4: Applications of Derivatives - Section 4.6 - Newton's Method - Exercises 4.6 - Page 231: 9

Answer

See graph and explanations.

Work Step by Step

Step 1. Given the function $f(x)=\begin{cases} \sqrt x, \ x\geq0 \\ \sqrt {-x}, \ x\lt0 \end{cases}$, we have $f'(x)=\begin{cases} \frac{1}{2\sqrt x}, \ x\geq0 \\ \frac{-1}{2\sqrt {-x}}, \ x\lt0 \end{cases}$ Step 2. Using Newton's Method, start with $x_0=h$; we have $x_1=x_0-\frac{f(x_0)}{f'(x_0)}=h-\frac{\sqrt h}{ \frac{1}{2\sqrt h}}=h-2h=-h$ Step 3. Starting with $x_0=-h$, we have $x_1=x_0-\frac{f(x_0)}{f'(x_0)}=-h-\frac{\sqrt {-(-h)}}{\frac{-1}{2\sqrt {-(-h)}}}=-h+2h=h$ Step 4. Graph the function as shown in the figure. The Newton's Method uses a tangent line to estimate the solutions. If we start at $x_0=h$ as shown in the figure, the tangent line will intersect with the x-axis at $x_1=-h$. Step 5. Similarly, we can draw a tangent line when we start with $x_0=-h$ and get $x_1=h$ as shown in the figure.
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.