Calculus 8th Edition

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

Appendix E - Sigma Notation - E Exercises - Page A38: 25



Work Step by Step

We expand and simplify the sum. We note that the terms alternate from -1 to 1. Since there are an even number of terms, the sum is 0. $\displaystyle \sum_{n=1}^{20}(-1)^{n}$ $=-1+1-1+1-1+1-1+1-1+1-1+1-1+1-1+1-1+1-1+1$ $=0$
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.