## Integrating Expressions Involving Fractions of Trigonometric Functions Using the substitution t=tan(1/2)theta

To be able to use this method we have to expressandin terms of

(1)

(2)

(3)

(4)

To evaluate any integral such asorwe make the substitutionand use (1), (2), (3) and (4) above to express everything in terms of t then integrate.

Example: Find

Sub (1) and (4)