&= (\ cos ^2 x-\ sin ^2 x) ^2-4\ cos ^2 x\ sin ^2 x-\ cos ^2 x (\ cos ^2 x-\ sin ^2 x) +2\ sin ^2 x\ cos ^2 x\ cos ^2 x\ \(\begin{align*} \sin(3x)-\cos x \sin(2x) &= \\ \sin(x+2x)-\cos x(2\sin x \cos ...&= (\ cos ^2 x-\ sin ^2 x) ^2-4\ cos ^2 x\ sin ^2 x-\ cos ^2 x (\ cos ^2 x-\ sin ^2 x) +2\ sin ^2 x\ cos ^2 x\ cos ^2 x\ sin(3x)−cosxsin(2x)=sin(x+2x)−cosx(2sinxcosx)=sinxcos(2x)+sin(2x)cosx−2sinxcos2x=sinx(cos2x−sin2x)+2sinxcosxcosx−2sinxcos2x=sinxcos2x−sin3x+0=cos2xsinx−sin3x=cos2xsinx−sin3x