1. The problem statement, all variables and given/known data For example with f(x,y) = x2y + xy2 2. Relevant equations 3. The attempt at a solution Well I know there is a critical point at (0,0). So I calculated the second derivatives but they are all 0 here so that doesn't help. I also tried using the Taylor expansion to show that f(x,y)>f(0,0) or not but that didn't get me anywhere. Then I tried considering the type of critical point on x=0,y=0,y=-x etc. but again I didn't get anywhere. Any ideas?