Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 7 - Trigonometric Identities and Equations - 7.3 Sum and Difference Identities - 7.3 Exercises - Page 678: 3



Work Step by Step

$\cos \left( \dfrac {\pi }{2}-x\right) =\cos \dfrac {\pi }{2}\cos x+\sin \dfrac {\pi }{2}\sin x=0\times \cos x+1\times \sin x=\sin x\Rightarrow 3\rightarrow D$
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.