title: matlab meshgrid parameter meaning confused
body: <pre><code>[X,Y] = meshgrid(-2:.2:2, -4:.4:4);
  </code></pre>
  
  <p>When I print the X and the X is 21*21 double.  </p>
  
  <p>I did not find any hint about the 21  in the meshgrid parameter, how it get the 21?</p>
  
  <p>Can somebody help to explain it?</p>