Prove that : `(sin3A+sin A)sin A+(cos3A-cos A)cos A=0`

8. (sin3A + sin A) sin A + (cos3A-cos A) cos A = 0

Prove that a) (sin3A + sinA)sinA+(cos3A-cosA) cosA=0 b) cos20^(@)cos40^(@)cos80^(@)=1/8 c) (sin8thetacostheta-sin6thetacos3theta)/(cos2thetacostheta-sin3thetasin4theta) = tan2theta

Prove that (sin3A+sinA)sinA+(cos3A-cosA)cosA=0

Prove that: (sin3x+sin x)sin x+(cos3x-cos x)cos x=0

Prove that (sin 3 x+sin x) sin x+(cos 3 x-cos x)cosx=0

( sin 3A + sin A) sin A + ( cos 3A- cos A ) cos A =

Prove that: (sin 3x + sin x) sin x + (cos 3x -cos x) cos x = 0

Prove that: (sin 3 x +sin x) sin x + (cos 3x - cos x) cos x = 0

Prove that : (sin A - sin B)/ (cos A + cos B) + (cos A - cos B)/ (sin A + sin B) = 0

Prove that: (sin A+sin3A)/(cos A-cos3A)=cotA