Nonuniform approximation of a function
<a rel="nofollow" class="external text" href="http://kulla.me">Stephan Kulla</a> (<a href="//commons.wikimedia.org/wiki/User:Stephan_Kulla" title="User:Stephan Kulla">User:Stephan Kulla</a>)
<span class="int-own-work" lang="en">Own work</span>