# How do you find critical points of multivariable function #f(x,y) =x^3 + xy - y^3#?

##### 1 Answer

Apr 11, 2015

Several notations and explanations are available. Here's one:

Find the partial derivatives, set them equal to zero and solve the resulting system of equations.

From the first equation:

So, we need:

and also when

The critical points are:

(I've heard that there is an alternative terminology that would find the values of