Question:
$\cos ^{3} x e^{\log \sin x}$
Solution:
$\cos ^{3} x e^{\log \sin x}=\cos ^{3} x \times \sin x$
Let $\cos x=t \Rightarrow-\sin x d x=d t$
$\Rightarrow \int \cos ^{3} x e^{\log \sin x} d x=\int \cos ^{3} x \sin x d x$
$=-\int t \cdot d t$
$=-\frac{t^{4}}{4}+C$
$=-\frac{\cos ^{4} x}{4}+C$