$\int \cos ^{5} x \sin x d x=f(x)+c$ হলে $f(x)=$ কত?

$\frac{\sin ^{6} x}{6}$

$\frac{-\sin ^{6} x}{6}$

$\frac{\cos ^{6} x}{6}$

$\frac{-\cos ^{6} x}{6}$