(cos2x-sin4x)/sin2x=ctg2x

[latex] \frac{cos2x-sin4x}{sin2x} =ctg2x[/latex] [latex]1. \frac{cos2x-sin4x}{sin2x}= \frac{cos2x}{sin2x}- \frac{sin4x}{sin2x}=ctg2x- \frac{2sin2x*cos2x}{sin2x}=ctg2x-2cos2x [/latex] [latex]2. ctg2x-2cos2x=ctg2x 2cos2x=0. cos2x=0[/latex] [latex]2x= \frac{ \pi }{2} + \pi n, n[/latex]∈Z [latex]x= \frac{ \pi }{4} + \frac{ \pi n}{2} , n[/latex]∈Z