Differentiate the function with respect to $x$: $\cos (\sin x)$

Let $f(x) = \cos (\sin x)$.
Using the chain rule,we differentiate with respect to $x$:
$\frac{d}{dx}[\cos (\sin x)] = -\sin (\sin x) \cdot \frac{d}{dx}(\sin x)$
Since $\frac{d}{dx}(\sin x) = \cos x$,we substitute this back:
$= -\sin (\sin x) \cdot \cos x$
$= -\cos x \sin (\sin x)$