Hi All,

I am stuck on these two problems. Basically, I understand the double angle identities, but not when sin or cos is square (i.e. sin^2(2x), etc)

Here are the problems...

1. -1/2(sec^2(x) = -2sin^2(x)csc^2(2x)

2. 1/2(sin(4x)) = 2sinxcosx - 4sin(sin^3(x))cos(x)

If my notation is screwy let me know...

Any help is appreciated. Thanks!