Mathematics - 25 August 2007

I got stucked after getting the next step: 2cos² 2x - 1 + cos x = 0, and I do not know how to continue..

Should I change the cos² 2x to (2cos² x -1)² ? But it looks more complicated..

2007-08-25 01:09:23 · 4 answers · asked by N.y.Rych 1