- Write everything in terms of sines and cosines.
(eg, tan A -> sinA/cosA, sec A = 1/cosA, etc)
- Multiply both sides through by whatever is necessary to get an equivalent equation with no fractional expressions
- Regroup terms so that you can use the Pythagorean identity
eg, sin3 A + cos2A sin A = (sin2 A + cos2 A) sin A
= 1 sin A