-cos9x cos7x=cos5x cos3x

cos4x cos8x-cos5x cos9x=0 if

Solve cos3x-cos4x=cos5x-cos6x

Prove : underset(xrarr0)"lim"(cos9x-cos7x)/(cos7x-cos5x)=(4)/(3)

Prove that (sin 9x+sin7+sin 3x+sin 5x)/(cos 9x+ cos 7x+ cos 3x+cos 5x)=tan 6x .

If x=(pi)/(48); then the value of (sin7x+sin5x+sin9x+sin3x)/(cos7x+cos5x+cos9x+cos3x) equals to

cos x+cos3x+cos5x+cos7x=0

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

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

Prove that (sinx+sin3x+sin5x+sin7x)/(cosx+cos3x+cos5x+cos7x)=tan4x

Let quad cos x+cos2x+cos3x+cos4x+cos5x+cos6x+cos7xy=(cos x+cos2x+cos3x+cos4x+cos5x+cos6x+cos7x)/(sin x+sin2x+sin3x+sin4x+sin5x+sin6x+sin7x), then which of the following holds good?