Question

What is the integral of `cos^3x` from 0 to pi?

Answer 1

Use trigonometric identities.

Explanation:

`cos^3x = cos^2x cosx = (1-sin^2x)cosx = cosx-sin^2xcosx`

So

`int cos^3x dx = int cosxdx - int sin^2xcosx dx`

`= sinx - 1/3sin^3x +C`