Differenciate this function:
I got :
Edit: Just fixed the problem, wrote it down incorrectly
Well, I would still follow dwsmith's advice and simplify first. What does that give you? (You can double-click on my LaTeX output to find out how to type in math. You need to use [tex] and [/ math] delimiters to get math to show up (although the closing one there should not have a space between the / and the math)).