## Calculus (3rd Edition)

$2sin(x)cos(x)$
The derivative of a product is equal to $u'v+uv'$. (Product Rule) Rewriting $sin^{2}(x)$ as $sin(x) \times sin(x)$ gives the derivative as $sin(x)(sin(x))'+(sin(x))'sin(x)$, or $2sin(x)cos(x)$.