1.Prove that sin(3x) = 4sinx.sin2x.sin4x
2.Solve : cosx(1+sin x/4 - 2cosx) + sinx (cosx/4 - 2sinx) = 0
3.solve : cos 3x + cos 2x = sin 3x/2 + sin x/2 , x=(0,pi)
4.solve for x and y : cos2x + cosx.cosy + cos2y = 0
Please solve quickly
1.Prove that sin(3x) = 4sinx.sin2x.sin4x
2.Solve : cosx(1+sin x/4 - 2cosx) + sinx (cosx/4 - 2sinx) = 0
3.solve : cos 3x + cos 2x = sin 3x/2 + sin x/2 , x=(0,pi)
4.solve for x and y : cos2x + cosx.cosy + cos2y = 0
Please solve quickly