Hey everyone, just wondering if anyone can figure this identity out.

$\displaystyle \ sin4x - sin2x/sin2x = \cos3x/cosx $

I already worked with the left side and ended up with $\displaystyle 2cos2x-1$ by using the double angle formula -> sin2x=2sinxcosx

Im stuck on what to do next.

any help is appreciated, thanks in advance.