I am studying for a test and can not firgure out how to do these problems:
Prove the identity:
1) sin 3x = ( sin x ) ( 4 cos^2(x) - 1 )
2) sin 3x = ( sin x ) ( 3 - 4 sin^2 (x) )
3) sin^4 (x) = ( 1/8 ) ( 3 - 4 cos 2x + cos 4x )
Solve the half angle Identities for all the solutions for the...