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

The value of 2 cos x - cos 3x - cos 5x is

Prove that cos ^(3) x sin ^(2) x = (1)/(16) (2cos x - cos 3x - cos 5x).

lim_(x->0) (cos2x-cos4x)/(cos3x-cos5x) =

Lim_(xrarr0)(cos2x-cos4x)/(cos3x-cos5x)= (A) (3)/(4) (B) -(3)/(4) (C) (4)/(3) (D) -(4)/(3)

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