Simplifying Trigonometric Equations

Hi all! I know this is probably a fairly simple concept for Trigonometry, but I can't quite remember how to do them. I'm just trying to make sure I know them well enough so that I can do them on a test I have in a few days. It would be awesome if you could just get me started on them.

1. $\displaystyle cot(x)sin(x) = \frac{\sqrt{3}}{2}$

2. $\displaystyle tan(x)$ • $\displaystyle cos(x) = 1$

3. $\displaystyle sin^2(x)$ + $\displaystyle cos^2(x) + cos(x)$ = 1

4. [$\displaystyle cot(x)$ • $\displaystyle (\frac{sin(x)}{cos(x)})$] • $\displaystyle sec^2(x)$ = $\displaystyle \frac{1}{2}$