Hey all,

Could I get some help on how to get the answers for these? I've been trying and I have no idea what I'm doing wrong:

1)[cos^-1(cos(-5pi/3))]

I got 2pi/3 since 0< 2pi/3 < pi

So the answer is 2pi/3?

2)[sin(x)/cos(-x)] + [sin (-x)/cos(x)]

Don't know where to start. Probably simpler than I'm making it....

3)csc[cos^-1(sqrt(2)/3)]

I got 3sqrt(2)/4

4)Establish the identity [cot/1-tan] + [tan/1-cot] = 1 + tan + cot

This one is so messy, basically I got stuck at

(cos/sin)(1 - cos/sin) + (sin/cos)(1- sin/cos)

5)Est. the identity cos(α-β)cos(α+β) = cos^2 α - sin^2 β

I kept foiling this over and over and the last time, I kept getting stuck at

(cos^2 α cos^2 β) - (sin α sinβ sin α sinβ)

Any help and explanations would be great, thanks.