Calculus: Trigonometric substitution (Part 3)

We look at integrals that can be solved by a clever trigonometric subsitution.

Usually we need to use some well-known trigonometric identities along the way to simplify the integral (after using a suitable trigonometric substitution).

In particular we solve a problem here for an integral which contains the term 'square of (x^2 - a^2)'.