Learn more: http://www.khanacademy.org/video?v=n4EK92CSuBE
Example of using trig substitution to solve an indefinite integral

Length: 8 minutes

Integrals: Trig Substitution 2

Length: 17 minutes

Integrals: Trig Substitution 3 (long problem)

Length: 15 minutes

Periodic Definite Integral