# What is the derivative of -sin^2(x)?

Feb 19, 2016

$f ' \left(x\right) = - \sin 2 x$
Given equation is $f \left(x\right) = - {\sin}^{2} \left(x\right)$
So, $f ' \left(x\right) = - \frac{d}{\mathrm{dx}} \left({\sin}^{2} \left(x\right)\right) = - 2 \sin x \frac{d}{\mathrm{dx}} \left(\sin x\right) = - 2 \sin x \cos x$