Plot of the <a href="https://en.wikipedia.org/wiki/arctangent" class="extiw" title="en:arctangent">arctangent</a> function <i>y</i>(<i>x</i>) = arctan(<i>x</i>) in the interval [-6,6] Multiple branches are shown and the solid line highlights the principal value.
<a href="//commons.wikimedia.org/wiki/User:Geek3" title="User:Geek3">Geek3</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>