<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >acosh</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="acos" HREF="function.acos.html"><LINK REL="NEXT" TITLE="asin" HREF="function.asin.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.acos.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.asin.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.acosh" ></A >acosh</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN108043" ></A ><P > (PHP 4 >= 4.1.0, PHP 5)</P >acosh -- 反双曲余弦</DIV ><DIV CLASS="refsect1" ><A NAME="AEN108046" ></A ><H2 >说明</H2 >float <B CLASS="methodname" >acosh</B > ( float arg )<BR ></BR ><P > 返回 <CODE CLASS="parameter" >arg</CODE > 的反双曲余弦值,即,其双曲余弦为 <CODE CLASS="parameter" >arg</CODE > 的那个值。 </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >注意: </B >本函数未在 Windows 平台下实现。</P ></BLOCKQUOTE ></DIV ><P > 参见 <A HREF="function.acos.html" ><B CLASS="function" >acos()</B ></A >, <A HREF="function.asinh.html" ><B CLASS="function" >asinh()</B ></A >, 和 <A HREF="function.atanh.html" ><B CLASS="function" >atanh()</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.acos.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.asin.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >acos</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" >asin</TD ></TR ></TABLE ></DIV ></BODY ></HTML >