`sin (n +1) x sin (n +2) x + cos (n +1) x cos (n +2) x = cos x`

cos ^(2) 2x -cos ^(2) 6x = sin 4x sin 8x

cos 4x =1- 8 sin ^(2) x cos ^(2) x

(sin 3x + sin x ) sin x + (cos 3x - cos x) cos x =0

Solve 2 sin^(2) x-5 sin x cos x -8 cos^(2) x=-2 .

((sin 7x + sin 5x ) +(sin 9x + sin 3x))/( (cos 7x + cos 5x ) + (cos 9x + cos 3x ))= tan 6x

The value of (cos^(4)x+cos^(2)x sin^(2) x + sin^(2)x)/(cos^(2)x+ sin^(2) x cos^(2) x + sin^(4)x) is ____________

If sin x+sin ^(2) x=1 then the value of cos ^(2) x+cos ^(4) x is

in (sin^(2)x)/(1+cos x) dx=