Proving Trigonometric Identities
This is a follow up to my last question.
1. Cot ( theta + pi) = cot theta
2. Csc 2 theta = 1/2 csc theta sec theta
3. Sin2 theta csc theta = 2 cos theta
4. Sec ( theta + 2pi) = sec theta
If you could prove with steps, that would fantastic.