## A quick way to classify stationary points for any $f(x,y)$.

There are several methods of going about classifying the stationary points of a function $f(x,y)$. Here I would like to show a method that I prefer which involves minimal calculation. Let us look at the example of begin{equation}f(x,y)=2x^3+6xy^2-3y^3-150xend{equation} It should be obvious from the 3D plot above that there are numerous stationary points on our […]