I'm have troubles with finding the general solution for [tex] \theta [\math] of:
$\displaystyle \cos(6\theta) + \cos(3\theta) + 4\cos^2 (\frac{3}{2}\theta)sin^2(\frac{3}{2}\theta) = 0 $
I know the cosine general formula is this:
$\displaystyle \pm\theta +2n\pi$
and that you can use identities to break the functions down until each factor can be zeroed and hence find these values. But the two additions are throwing me at the start amongst other things.
Your help would be greatly appreciated.
D