Whenever you are faced with a problem to solve start trying to solve it with the methods at hand.
1, You surely know how to do a goolge-search, so try a search for something like "double-integral matlab", and look for some of the answers that seems relevant.
2, When using matlab you should learn about using the commands lookfor and help, try something like this:
3, after that you should be able to start to zoom in on the integral functions. Now you're ready to read the help and documentation of integral2.