use the formulas
to keep breaking down the sines and cosines until you get them to and . then use the double angle formulas. then simplify and continue. it will be a lot of work, but it is the kind of work where you can keep following your nose
use the double angle formulas for sine15. sin2x = cosx
(on the interval [0, 2pi])
EDIT: This is my 53th post!!!!!!!