title: MATLAB fplot3 command
body: <p>I wanted to plot the 3D surface ((e^-t)sint,(e^-t)cost,1) using the following code.</p>
  
  <pre><code>x=(exp(-t))*sin(t); y=(exp(-t))*cos(t); z=1;
      fplot3(x,y,z)
  </code></pre>
  
  <p>I received this error message:</p>
  
  <pre><code>Error using fplot3 (line 46)
  Expected input to be one of these types:
  
  function_handle, sym
  
  Instead its type was double.
  </code></pre>