When integrating integrals of the form sin³ sin cosa da where i is even and k is odd, you should x O rewrite cos* z as cost-1 cos a and use the Pythagorean identity to rewrite the even powered cosine in terms of sine. Integrate with u = cos x. O rewrite cos* a as cost-1x cosa and use the Pythagorean identity to rewrite the even powered cosine in terms of sine. Integrate with u = sin 2. O rewrite sinzas sina sina and use the Pythagorean identity to rewrite the even powered sine in terms of cosine. Integrate with u = cos . O rewrite sin a as sin sina and use the Pythagorean identity to rewrite the even powered sine in terms of cosine. Integrate with u = sin x.