College Algebra 7th Edition

Published by Brooks Cole
ISBN 10: 1305115546
ISBN 13: 978-1-30511-554-5

Chapter 8, Sequences and Series - Section 8.1 - Sequences and Summation Notation - 8.1 Exercises - Page 601: 50



Work Step by Step

We evaluate the sum: $\sum_{j=1}^{100}(-1)^{j}=(-1)^{1}+(-1)^{2}+(-1)^{3}+(-1)^{4}+(-1)^{5}+...+(-1)^{99}+(-1)^{100}=-1+1-1+1-1+...-1+1=0$ (Since we have an even number of terms, the $+1$ and $-1$ cancel out.)
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