tifier">acosh</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">complex</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;&amp;</span> <span class="identifier">z</span><span class="special">);</span>
</pre>
<p>
      <span class="bold"><strong>Effects: </strong></span> returns the inverse hyperbolic cosine
      of the complex number z.
    </p>
<p>
