Esta seccion del curso esta dedicada a la creacion de curvas de nivel en LaTeX.
Linea a incluir:

-shell-escape -enable-write18

\documentclass{article}
% Autor: Favian Arenas
% farenasenator@gmail.com
\usepackage{tikz,color}
\usepackage{pgfplots}
\usepackage{tikz-3dplot}
\pgfplotsset{width=15cm,compat=1.12}
\begin{document}
{\Huge$$(x^2+3y^2)e^{1-x^2-y^2}$$}
\begin{tikzpicture}
   \begin{axis}
     [xlabel=$x$,ylabel=$y$,view={0}{90}]
     \addplot3[contour gnuplot={number=15,labels=false},
               thick,
               domain=-2:2,domain y=-2:2]
  {(x^2+3*y^2)*exp(1-x^2-y^2)};
  \end{axis}
\end{tikzpicture}
\end{document}