I have some understanding of how to solve problems involving compact domains. Set the gradient to zero and solve for x and y, and then try to parameterize if needed to find max/min over the border of the domain. The thing is, my book doesn't go into much detail on how to do optimize functions defined over non-compact domains. It basically says to try to narrow the domain down to a compact domain, and then optimize using the "method" described above. There are some examples too but they're not really helping me. Does anyone have any good links to sites discussing some methods/problems? Or if you have any tips yourself? Oh and by compact domain I mean that it is confined and closed. It's multivariable functions by the way.