#### Answer

A

#### Work Step by Step

$\cos \left( x-y\right) =\cos x\cos y+\sin x\sin y\Rightarrow 2\rightarrow A$

Published by
Pearson

ISBN 10:
013421742X

ISBN 13:
978-0-13421-742-0

A

$\cos \left( x-y\right) =\cos x\cos y+\sin x\sin y\Rightarrow 2\rightarrow A$

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