uTools-Manuals/docs/php/expm1.html
2019-04-28 19:00:34 +08:00

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<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>返回 exp(number) - 1甚至当 number 的值接近零也能计算出准确结果</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.expm1" class="refentry">
<div class="refnamediv">
<h1 class="refname">expm1</h1>
<p class="verinfo">(PHP 4 &gt;= 4.1.0, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">expm1</span> &mdash; <span class="dc-title">
返回 exp(number) - 1甚至当 number 的值接近零也能计算出准确结果
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.expm1-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>expm1</strong></span>
( <span class="methodparam"><span class="type">float</span> <code class="parameter">$arg</code></span>
) : <span class="type">float</span></div>
<p class="para rdfs-comment">
<span class="function"><strong>expm1()</strong></span> 返回 &#039;exp(<code class="parameter">number</code>) - 1&#039;,甚至当
<code class="parameter">number</code> 的值接近零也能计算出准确结果。但是当两个数值趋近于相等的时候,
&#039;exp (<code class="parameter">number</code>) - 1&#039; 就会变得不太准确。
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.expm1-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">arg</code></dt>
<dd>
<p class="para">
要处理的参数
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.expm1-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
&#039;e&#039; to the power of <code class="parameter">arg</code> minus one
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.expm1-changelog">
<h3 class="title">更新日志</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>版本</th>
<th>说明</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.3.0</td>
<td>
此函数在所有平台上均可用
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.expm1-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="log1p.html" class="function" rel="rdfs-seeAlso">log1p()</a> - 返回 log(1 + number),甚至当 number 的值接近零也能计算出准确结果</span></li>
<li class="member"><span class="function"><a href="exp.html" class="function" rel="rdfs-seeAlso">exp()</a> - 计算 e 的指数</span></li>
</ul>
</p>
</div>
</div></div></div></body></html>