Answer
$=8-16+...+(-1)^{n+1}2^n$
Work Step by Step
$\sum_{k=3}^{n} ((-1)^{k+1}2^k)=((-1)^{3+1}2^3)+((-1)^{4+1}2^4)+...+((-1)^{n+1}2^n)=8-16+...+(-1)^{n+1}2^n$
Precalculus (10th Edition)
by Sullivan, Michael
Published by
Pearson
ISBN 10:
0-32197-907-9
ISBN 13:
978-0-32197-907-0
Chapter 12 - Sequences; Induction; the Binomial Theorem - 12.1 Sequences - 12.1 Assess Your Understanding - Page 807: 58
Update this answer!
You can help us out by revising, improving and updating this answer.
Update this answerAfter 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.
