Update optlab.html

optlab/optlab.html

@@ -52,7 +52,7 @@
   direct and adjoint formulations<a href="#2"><sup>2</sup></a>. To test OPTLAB:
 </p>
 <ol>
-  <li>Dowload the <a href="http://onelab.info">ONELAB software bundle</a>
+  <li>Download the <a href="http://onelab.info">ONELAB software bundle</a>
   <li>Launch the app <img src="http://geuz.org/gmsh/gallery/icon.png" height=20px>
   <li>Open <code>tutorials/optlab/Team25/shape.py</code> or <code>tutorials/optlab/Lbracket/topo.py</code>
   <li>Press <code>Run</code>