Solve `cos3x-cos4x=cos5x-cos6x`

Solve: cos4x=cos2x

Solve: cos4x=cos2x

Solve: cos4x=cos2x

2cos x-cos3x-cos5x=

Solve the following equations cos 3 x - cos 4x = cos 5x - cos 6x

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?

(Solve): cos6x+cos4x=sin3x+sin x

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

Solve sin5x.cos3x=sin6x.cos2x.