1. Be very proficient in doing algebra.

2. Know all your trig identities:

The reciprocal identities:





The quotient identities




The Pythagorean identities 

 



as well as all of their rearrangements:






Also recognize factors of the Pythagorean
identities which can be written as the
difference of two perfect squares, such
as recognizing that since






that when one of the factors on the right
appears, that you can multiply top and bottom 
by another factor and a Pythagorean identity 
will arise.


3.  Work with the most complicated side first.
    Then when you have simplified it as far
    as you can, and the identity has not
    been solved, begin to work with the other
    side to see if you can get it to an equivalent
    form.

4.  If you are stuck, try using the reciprocal and
    quotient formulas so that only sines and cosines
    appear. 

Edwin