Hi, I solved tan(5pi/12) using the sum/difference formulas and came up with the following:

(1/sqrt(3) + 1) / (-1/sqrt(3) + 1)

I know it simplifies further down into: 2 + sqrt(3), however I suppose I have forgotten some of the rules of simplification. I don't know how to get it down to that. If someone could explain how to simplify these sorts of expression, that would be much appreciated. Thanks!