Landos

I want the geometrical interpretation of the following: > If fxx * fyy} < fxy^2 and fxx has the same sign as fyy at a point, then why is that point a saddle point? Because,in the case that they have the same sign,one would expect that point to be a minimum or maximum point,not a saddle point. Bear in mind,that i have checked the intuitive explanation that is available in wikipedia,but did not understand it. Also, i am studying physics and not math,so please don't complicate things with symbolisms that i might not understand. Also, i want an intuitive answer,because i know the maths behind categorizing critical points.