Calculus 10th Edition

Published by Brooks Cole
ISBN 10: 1-28505-709-0
ISBN 13: 978-1-28505-709-5

Chapter 9 - Infinite Series - 9.2 Exercises - Page 601: 31

Answer

$\displaystyle \frac{1}{2}$

Work Step by Step

$\displaystyle \sum_{n=0}^{\infty}(\frac{1}{2^{n}}-\frac{1}{3^{n}})=\sum_{n=0}^{\infty}(\frac{1}{2})^{n}-\sum_{n=0}^{\infty}(\frac{1}{3})^{n}$ Both are geometric series, the first with $a=1, r=\displaystyle \frac{1}{2} < 1$ the second with $a=1, r=\displaystyle \frac{1}{3} < 1$. (both converge by Th 9/6, $\displaystyle \sum_{n=0}^{\infty}ar^{n}=\frac{a}{1-r}$) $\displaystyle \sum_{n=0}^{\infty}(\frac{1}{2^{n}}-\frac{1}{3^{n}})=\frac{1}{1-(\frac{1}{2})}-\frac{1}{1-(\frac{1}{3})}$ $=\displaystyle \frac{1}{\frac{1}{2}}-\frac{1}{\frac{2}{3}}$ $=2-\displaystyle \frac{3}{2}$ $=\displaystyle \frac{1}{2}$
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.