Use your exponent rules.
This is also good for the square root question.
As far as the angle between the vectors...
Have you met the "Vector Inner Product"? Perhaps we should use the method of slopes? There are a few ways to go about it.
On the last, is the exponent "0" just a typo? Perhaps you meant ? In any case, just solve it.
-2sin(x) + 3 = 4
-2sin(x) = 1
sin(x) = -1/2
You should know values of x that have this sine value. Think "Quadrant" before you believe you are done.