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: 6



Work Step by Step

$\sin \left( x-\dfrac {\pi }{2}\right) =\sin x\cos \dfrac {\pi }{2}-\cos x\sin \dfrac {\pi }{2}=\sin x\times 0-\cos x\times 1=-\cos x\Rightarrow 6\rightarrow B$
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