Let f(x,y)=((x^(2)y^(2))/(x^(2)+y^(2))), classify the behavior of f near the critical point (0,0).
but the following works:
Along the and axes the function is a constant equal to zero. Along
any other ray through the origin we may put , when:
which has a quadratic like mininum at .
A surface plot shows what this looks like (see attachment)
(this assumes that we give the function a value of at )