Question

Find: `int cos^3 x  e^(log sin x)  dx` 

Answer 1

Let I = `int cos^3 x  e^(log sin x) dx`

or I = `int cos^3 x  sin  x  dx`

Put cos x = t ⇒ − sin x dx = dt

∴ I = `-intt^3 dt`

or, I = `-t^4/4 + C`

or, I = `-cos^4x/4 + C`