How do I use power reducing forumlas for these two equations

I keep trying to do it myself, but I always end up with the wrong answers:
1. 3 sin^4(x)
2. 128 sin^2(x) cos^2(x)

Can anyone show me the step-by-step process?

1. 3 sin^4(x)
= 3 (sin x)^4
2. 128 sin^2(x) cos^2(x)
=32* 4 sin^2(x) cos^2(x)
=32 ( 2 sin x cos x)^2
=32 ( sin 2x)^2
=32 sin^2 2x

1)
9/8 - 3/2 Cos[2 x] + 3/8 Cos[4 x]

2)
16 - 16 Cos[4 x]