proportional Gudermannian-function curve [-4.5|4.5] <br> very accurate gudermannian plot with cubic bezier-curves. Labels in embedded "Computer Modern" font
<a href="//commons.wikimedia.org/wiki/User:Geek3" title="User:Geek3">Geek3</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>