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<title>Square root</title>
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<h1 class="refname">sqrt</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">sqrt</span> — <span class="dc-title">Square root</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.sqrt-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">float</span> <span class="methodname"><strong>sqrt</strong></span>
( <span class="methodparam"><span class="type">float</span> <code class="parameter">$arg</code></span>
)</div>
<p class="para rdfs-comment">
Returns the square root of <em><code class="parameter">arg</code></em>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.sqrt-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">arg</code></em></span>
<dd>
<p class="para">
The argument to process
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.sqrt-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
The square root of <em><code class="parameter">arg</code></em>
or the special value <em>NAN</em> for negative numbers.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.sqrt-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3478">
<p><strong>Example #1 <span class="function"><strong>sqrt()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Precision depends on your precision directive<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">sqrt</span><span style="color: #007700">(</span><span style="color: #0000BB">9</span><span style="color: #007700">); </span><span style="color: #FF8000">// 3<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">sqrt</span><span style="color: #007700">(</span><span style="color: #0000BB">10</span><span style="color: #007700">); </span><span style="color: #FF8000">// 3.16227766 ...<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.sqrt-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.pow.html" class="function" rel="rdfs-seeAlso">pow()</a> - Exponential expression</span></li>
</ul>
</p>
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