If the equation contains trig functions with the same angle and some of them are squared then it may be possible to use a Pythagorean identity to write an equation in the same trig. function which may then possibly factorise.
In these examples I show you how the Pythagorean identities help solve some equations.
- sin2θ + cos2θ ≡ 1
- 1 + tan2θ ≡ sec2θ
- 1 + cot2θ ≡ cosec2θ