I have to solve cos4x=sin2x where x is an element of 0, 360.

The problem, for me, is cos4x. I haven't proved this myself, but a quick search gave me that cos4x=$\displaystyle 8cos^4x-8cos^2x+1$

By going along the lines of $\displaystyle 8cos^4x-8cos^2x+1=2sinxcosx$ (see original question) I managed to arrive at sinx=$\displaystyle \frac{1}{3}$

This does not give an exact value and I was wondering if I had done this correctly. Thanks!