Sin^2.3x + 4sin3xcos3x - 5cos^2.3x = 0

1) sin^2.3x + 4sin3xcos3x - 5cos^2.3x=0
2) sin^2.x/2 + 2sinx/2.cosx/2 - 2 cos^2.x/2 = 1/2
giúp e 2 bài này vs ạ, em cám ơn ạ