Question

Find the antiderivative using Trigonometric Substitution:

(cosx)^3

Answer 1

rewrite (cosx)^3 = cos^2x 8 cosx = (1 - sin^2x)*cosx
let u=sinx, du=cosx dx

so your integral is now

Answer 2

integral (1-u^2) du

Answer 3

oh.. trig substitution? why?

Answer 4

u-sub works fine here...