prove that:
sin5x-2sin3x+sinx/cos5x-cosx= tanx
= (sin5x + sinx -2sin3x)/(cos5x - cos x)
= (2sin3xcos2x - 2sin3x)/(-2sin3xsin2x)
= 2sin3x(cos2x - 1)/(-2sin3xsin2x)
= cos2x - 1/(-sin2x)
= (1 - 2sin²x) - 1/(-2sinxcosx)
= -2sin²x/-2sinxcosx
=Sinx/cosx =tanx