Trig test tomorrow. please, please help!

Ok, so I have a test tomorrow. My teacher is an Algebra teacher and doesn't really know how to explain Trig all that much, so all of us in her class are a little confused. I went in for help, and I really just don't understand any of it. It seems like I understand it more when someone else explains it, so if someone could help that'd be amazinggg.

A: It says determine the coordinate point. I know that that means either (√2/2, √2/2), (1/2, √3/2), or (√3,2, 1/2) and I know that those coordinates corresponds to it being pi/3, pi/4 or pi/6 but how do I know if it's negative or positive and what quadrant it's in?

B: How do you evaluate a trig function?

Example: sin 7pi/2

C: The question is find cotO, if cscO=6, with O in quadrant II

Then it says for another similar question, csc^2 121^0 -cot^2 121^0

D:Find the remaining trig functions given sinO = 1/√3 and cosO=5/√3

(I do this like Pythagorean theorem right?)

Thank you sooo much to whoever answers these. You can answer one or all of them, it doesn't matter. Any help I can get is amazing. Thank you :)