Wacky change of variables for Multi integration!!! Arghh im having diffiiculty with these problems. I am having difficulty mastering the LaTeX form--- (things like how to make a double integral etc) so if you look at this site http://www.math.washington.edu/~m124/Stewart5Eprobs/5ET-15problems.pdf and look at page 1040 in the text (ch 15.9) the problem in question is number 14... I am having a really tough time rewriting the integrand in u,v form with the given transformation. Perhaps there was a mistake in my algebra--- but what would be the way to go about doing this? and also for number 20... would the proper transformation be u = x+y and v = x^2 - y^2 ? Or would something else work better. Again I apologize for posting a link--- I promise I will take the time to learn LaTeX before I post--- I just have a tough time with Change Of Variables overall. Thanks for all your help.