Welcome to Math Help Forum!
- Post only one question at a time. (Have a look at the Rules - particularly #14.)
- If you can show us the attempt that you've made, that will help to identify exactly where the problem is. As it is, it just looks as if you want someone to do your homework for you!
Having said that, let me give you some clues for the first two questions:
(1) I'm sure you know that . So use a calculator to find the principal value. Then look at how the values of (and therefore repeat:
(2) Do you know the formulae: