Lost some basic skills, working with a square root

Okay, so I'm doing a TON of identities in trig, and have come to a point where I'm working on problems such as:

$\displaystyle \sqrt(1+cos(30))/2$

cos of 30 is $\displaystyle \sqrt3/2$

I've forgotten what it's called but I need a step by step guide to simplifying this! (it simplifies down to an exact answer of $\displaystyle \sqrt(2+\sqrt3)/2$

Edit: Yes, I've done college algebra (and aced it) but I haven't had to simplify problems like this in about 6 or 7 months, so I've lost the skill!