<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >exp</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="Math 数学函数" HREF="ref.math.html"><LINK REL="PREVIOUS" TITLE="deg2rad" HREF="function.deg2rad.html"><LINK REL="NEXT" TITLE="expm1" HREF="function.expm1.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.deg2rad.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.expm1.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.exp" ></A >exp</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN108410" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >exp -- 计算 <TT CLASS="constant" ><B >e</B ></TT > 的指数</DIV ><DIV CLASS="refsect1" ><A NAME="AEN108414" ></A ><H2 >说明</H2 >float <B CLASS="methodname" >exp</B > ( float arg )<BR ></BR ><P > 返回 <TT CLASS="constant" ><B >e</B ></TT > 的 <CODE CLASS="parameter" >arg</CODE > 次方值。 </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >注意: </B > 用 'e' 作为自然对数的底 2.718282. </P ></BLOCKQUOTE ></DIV ><P > <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN108428" ></A ><P ><B >例 1. <B CLASS="function" >exp()</B > 范例</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /></font><font color="#007700">echo </font><font color="#0000BB">exp</font><font color="#007700">(</font><font color="#0000BB">12</font><font color="#007700">) . </font><font color="#DD0000">"\n"</font><font color="#007700">;<br />echo </font><font color="#0000BB">exp</font><font color="#007700">(</font><font color="#0000BB">5.7</font><font color="#007700">);<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ><P >上例将输出:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="screen" >1.6275E+005 298.87</PRE ></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ><P > 参见 <A HREF="function.log.html" ><B CLASS="function" >log()</B ></A > 和 <A HREF="function.pow.html" ><B CLASS="function" >pow()</B ></A >。 </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.deg2rad.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.expm1.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >deg2rad</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.math.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >expm1</TD ></TR ></TABLE ></DIV ></BODY ></HTML >