Hi...again.

I know I'm a bother but can you guys help me again?

I'm having trouble with these ones. Thanks!

1. find the exact solutions algebraically in the interval [0, 2pi)

sin 2x sin x = cos x. (2 is not an exponent on this one)

2. verify identity algebraically

cos^4 x - sin^4 x = cos 2x.

3. find all solutions of the equation in the interval [0, 2pi)

sin(x + pi/6) - sin(x - pi/6) = 1/2