2cos x-cos3x-cos5x=

2cosx-cos3x-cos5x= ............... A) 16 cos ^(3) x sin ^(2) x B) 16 sin^(2) x cos ^(2) x C) 4 cos ^(2) x sin ^(2) x D) 4 sin ^(2) x cos ^(2)x

Prove the following: (frac(sinx-sin3x+sin5x-sin7x)(cosx-cos3x-cos5x+cos7x))=cot2x

Prove that cos x+cos3x+cos5x+cos(2n-1)x=(sin2nx)/(2)sin x

cos x+cos3x+cos5x+cos7x=0

Prove that (sin9x+sin7x+sin3x+sin5x) /(cos9x+cos7x+cos3x+cos5x)=tan6x ?

The fundamental period of (sin x+sin3x+sin5x+sin7x)/(cos x+cos3x+cos5x+cos7x) is (pi)/(k) then k=

Differentiate. (cos 3x-cosx)/(cos5x-cos3x)