I don't know how to text in the limits but the interior are and , and the exterior are 0 and 2.
What do I do with this please?
While what ChiSigma said is correct, it's only valid to separate the variables if the variables can be separated, as they can be in this case. A better way in my opinion, is to perform the innermost integration of the ENTIRE function, then the outer integration of the entire function. This will work in ALL cases.
So in your case...