Question

Inregrate $\int \frac{\cos x dx}{\sin^2 x}$

Answer 1

$\int \cfrac{\cos x dx}{\sin^2x} = [t = \sin x, dt = \cos x dx] = \int \cfrac{dt}{t^2} = -\cfrac{1}{t}+C=-\cfrac{1}{\sin x}+C$