#### Answer

$C$

#### Work Step by Step

$\cos \alpha =\sqrt {\dfrac {1+\cos 2\alpha }{2}}\Rightarrow \cos 75=\sqrt {\dfrac {1+\cos 150}{2}}\Rightarrow 22\rightarrow C$

Published by
Pearson

ISBN 10:
013421742X

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

$C$

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