# How do you find the derivative of f(x)=sin8x?

$f ' \left(x\right) = 8 \cos \left(8 x\right)$
This will require a single application of the Chain Rule, as a result of the $8 x .$
$f ' \left(x\right) = \cos \left(8 x\right) \cdot \frac{d}{\mathrm{dx}} 8 x$
$f ' \left(x\right) = 8 \cos \left(8 x\right)$