Answer
Differentiate $y=\sin \theta \cos \theta$
$y'=\cos 2\theta$
Work Step by Step
Differentiate using product and trig rules.
$y' = \sin \theta ' \cos \theta + \sin \theta \cos \theta '$
$=\cos ^2 \theta - \sin ^2 \theta$
Simplify using trig identities.
= $\cos 2\theta$
