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<title>Exponential expression</title>
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<h1 class="refname">pow</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">pow</span> — <span class="dc-title">Exponential expression</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.pow-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.pseudo-types.html#language.types.number" class="type number">number</a></span> <span class="methodname"><strong>pow</strong></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.number" class="type number">number</a></span> <code class="parameter">$base</code></span>
, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.number" class="type number">number</a></span> <code class="parameter">$exp</code></span>
)</div>
<p class="para rdfs-comment">
Returns <code class="parameter">base</code> raised to the power of
<code class="parameter">exp</code>.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
In PHP 5.6 onwards, you may prefer to use the
<a href="language.operators.arithmetic.html" class="link">**</a> operator.
</p>
</p></blockquote>
</div>
<div class="refsect1 parameters" id="refsect1-function.pow-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">base</code></dt>
<dd>
<p class="para">
The base to use
</p>
</dd>
<dt>
<code class="parameter">exp</code></dt>
<dd>
<p class="para">
The exponent
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.pow-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
<code class="parameter">base</code> raised to the power of <code class="parameter">exp</code>.
If both arguments are non-negative integers and the result can be represented
as an integer, the result will be returned with <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span> type,
otherwise it will be returned as a <span class="type"><a href="language.types.float.html" class="type float">float</a></span>.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.pow-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4267">
<p><strong>Example #1 Some examples of <span class="function"><strong>pow()</strong></span></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">pow</span><span style="color: #007700">(</span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">8</span><span style="color: #007700">)); </span><span style="color: #FF8000">// int(256)<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">pow</span><span style="color: #007700">(-</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">20</span><span style="color: #007700">); </span><span style="color: #FF8000">// 1<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">pow</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">); </span><span style="color: #FF8000">// 1<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">pow</span><span style="color: #007700">(</span><span style="color: #0000BB">10</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0.1<br /><br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">pow</span><span style="color: #007700">(-</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">5.5</span><span style="color: #007700">); </span><span style="color: #FF8000">// PHP >=5.2.2: NAN<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">pow</span><span style="color: #007700">(-</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">5.5</span><span style="color: #007700">); </span><span style="color: #FF8000">// PHP <5.2.2: -NAN<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.pow-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
This function will convert all input to a number, even non-scalar values,
which could lead to <em>weird</em> results.
</p>
</p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.pow-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.exp.html" class="function" rel="rdfs-seeAlso">exp()</a> - Calculates the exponent of e</span></li>
<li class="member"><span class="function"><a href="function.sqrt.html" class="function" rel="rdfs-seeAlso">sqrt()</a> - Square root</span></li>
<li class="member"><span class="function"><a href="function.bcpow.html" class="function" rel="rdfs-seeAlso">bcpow()</a> - Raise an arbitrary precision number to another</span></li>
<li class="member"><span class="function"><a href="function.gmp-pow.html" class="function" rel="rdfs-seeAlso">gmp_pow()</a> - Raise number into power</span></li>
</ul>
</p>
</div>
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