### Video Summary:

Learn the fundamental identities.
Try to rewrite the more complicated side of the equation so that it is identical to the simpler side.
It is often helpful to express all functions in terms of sine and cosine and then simplify the result.
Usually, any factoring or indicated algebraic operations should be performed. For example,
As you select substitutions, keep in mind the side you are not changing, because it represents your goal.
If an expression contains 1 + sin x, multiplying both numerator and denominator by 1 – sin x would give 1 – sin² x, which could be replaced with cos² x.