I have the following equation, and I have been stumped on it for a long time now, I was wondering if I could get some hints in attempting to solve it.
$ 2\cos^2\theta-\cos\theta-1 = \sin^2\theta $
Solved!
Use the hyperbolic function (Thanks svenkatr):
$ \cos^2\theta - \sin^2\theta = 1 $