title: Differences in graphs 3D plot with functions
body: <p>I have this function:</p>
  
  <p><a href="https://i.stack.imgur.com/jqj2z.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jqj2z.gif" alt="enter image description here"></a></p>
  
  <p>In WolframAlpha this is the Graph:</p>
  
  <p><a href="https://i.stack.imgur.com/T5wQE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/T5wQE.png" alt="Wolfram"></a></p>
  
  <p>And in MatLab I use this code:</p>
  
  <pre><code>clc; clear; close all
  [x,y]=meshgrid(-1:.1:1);
  e = exp(1);
  z=(e^-x^2)+((e^-2)*(y^2))
  surf(x,y,real(z));
  </code></pre>
  
  <p>And print this graph:</p>
  
  <p><a href="https://i.stack.imgur.com/dVlMJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dVlMJ.png" alt="MatLab"></a></p>
  
  <p>Why does this difference occur? what am I doing wrong?</p>