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<h1 class="refname">atan</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">atan</span> — <span class="dc-title">Arkustangens</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.atan-description">
<h3 class="title">Beschreibung</h3>
<div class="methodsynopsis dc-description">
<span class="type">float</span> <span class="methodname"><strong>atan</strong></span>
( <span class="methodparam"><span class="type">float</span> <code class="parameter">$arg</code></span>
)</div>
<p class="para rdfs-comment">
Berechnet den Arkustangens von <code class="parameter">arg</code>.
<span class="function"><strong>atan()</strong></span> ist die Komplementärfunktion zu
<span class="function"><a href="function.tan.html" class="function">tan()</a></span>, d.h. für alle Werte im Wertebereich
von <span class="function"><strong>atan()</strong></span> gilt <em>a==tan(atan(a))</em>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.atan-parameters">
<h3 class="title">Parameter-Liste</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">arg</code></dt>
<dd>
<p class="para">
Der zu verarbeitende Wert
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.atan-returnvalues">
<h3 class="title">Rückgabewerte</h3>
<p class="para">
Der Arkustangens von <code class="parameter">arg</code> in Bogenmaß.
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.atan-seealso">
<h3 class="title">Siehe auch</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.tan.html" class="function" rel="rdfs-seeAlso">tan()</a> - Tangens</span></li>
<li class="member"><span class="function"><a href="function.atanh.html" class="function" rel="rdfs-seeAlso">atanh()</a> - Areatangens Hyperbolikus</span></li>
<li class="member"><span class="function"><a href="function.asin.html" class="function" rel="rdfs-seeAlso">asin()</a> - Arkussinus</span></li>
<li class="member"><span class="function"><a href="function.acos.html" class="function" rel="rdfs-seeAlso">acos()</a> - Arkuskosinus</span></li>
</ul>
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