Extremely Urgent Trig Help Needed

I have an assignment to turn in tomorrow that will be a large part of my grade. I have had virtually no time to work over break and many other things to work on. Yada yada yada everyone rationalizes why they didn't get stuff done so it doesn't really matter why. I need to know how to do these problems by tomorrow morning. If someone was kind enough to type out the explanations I could finish it during lunch easily, I used to know how but forgot over a couple weeks, guess that goes to show my learning wasn't very deep.

So here are the problems I will need to know by tomorrow. I appreciate anyone who can help me out right away.

1. $\displaystyle \sin 2 \theta \ = 1/2 $

2. $\displaystyle

3 \sqrt{2} \sin \theta + 2 = -1 $

3. $\displaystyle 2 \sin^2 \ theta\ - 3 \cos \theta +1 = 0 $

4. $\displaystyle \cos 2\ theta = cos \ theta \ $

Any and all help right away is very much appreciated. As I said this is really important and urgent.