<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >asin</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="acosh" HREF="function.acosh.html"><LINK REL="NEXT" TITLE="asinh" HREF="function.asinh.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.acosh.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.asinh.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.asin" ></A >asin</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN108064" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >asin -- 反正弦</DIV ><DIV CLASS="refsect1" ><A NAME="AEN108067" ></A ><H2 >说明</H2 >float <B CLASS="methodname" >asin</B > ( float arg )<BR ></BR ><P > 返回 <CODE CLASS="parameter" >arg</CODE > 的反正弦值,单位是弧度。<B CLASS="function" >asin()</B > 是 <A HREF="function.sin.html" ><B CLASS="function" >sin()</B ></A > 的反函数,它的意思是在 <B CLASS="function" >asin()</B > 范围里的每个值都是 <TT CLASS="literal" >a==sin(asin(a))</TT > 。 </P ><P > 参见 <A HREF="function.asinh.html" ><B CLASS="function" >asinh()</B ></A >, <A HREF="function.acos.html" ><B CLASS="function" >acos()</B ></A > 和 <A HREF="function.atan.html" ><B CLASS="function" >atan()</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.acosh.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.asinh.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >acosh</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" >asinh</TD ></TR ></TABLE ></DIV ></BODY ></HTML >