Prove that:`cos^2 2x-cos^2 6x=sin4xsin8x`

Prove that: cos^(2)2x-cos^(2)6x=sin4x sin8x

Prove that: cos^(2)2x-cos^(2)6x=s in4xs in8x

Prove that: (cos x+cos y)^(2)+(sin x-sin y)^(2)=4cos^(2)backslash(x+y)/(2)

Prove that: (i) "sin"^(2)6x-"sin"^(2)4x="sin" 2x sin 10x (ii) cos^(2)2x-cos^(2)6x="sin" 4x sin 8x .

Prove that cos8x-cos5x=-2sin((13x)/(2))sin((3x)/(2))

Prove that: quad (cos x-cos y)^(2)+(sin x-sin y)^(2)=4sin^(2)(x-y)/(2)

Prove that (cos 3 x)/(sin 2 xsin 4x)+(cos 5x)/(sin 4xsin 6x)+(cos 7x)/(sin 6xsin 8x)+(cos 9x)/(sin 8x sin 10x) =(1)/(2) (co sec x)[co sec2x-co sec 10x]

prove that cos x cos2x cos4x cos8x=(sin16x)/(16sin x)

Prove that :cos4x=1-8sin^(2)x cos^(2)x