<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML ><HEAD ><TITLE >asin</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Manual PHP" HREF="index.html"><LINK REL="UP" TITLE="Mathematical Functions" 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=ISO-8859-2"></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" >Manual PHP</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.acosh.html" ACCESSKEY="P" >Înapoi</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.asinh.html" ACCESSKEY="N" >Înainte</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.asin" ></A >asin</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN49953" ></A ><P > (PHP 3, PHP 4 , PHP 5)</P >asin -- Arc sine</DIV ><DIV CLASS="refsect1" ><A NAME="AEN49956" ></A ><H2 >Description</H2 >float <B CLASS="methodname" >asin</B > ( float arg)<BR ></BR ><P > Returns the arc sine of <VAR CLASS="parameter" >arg</VAR > in radians. <B CLASS="function" >asin()</B > is the complementary function of <A HREF="function.sin.html" ><B CLASS="function" >sin()</B ></A >, which means that <VAR CLASS="literal" >a==sin(asin(a))</VAR > for every value of a that is within <B CLASS="function" >asin()</B >'s range. </P ><P > See also: <A HREF="function.asinh.html" ><B CLASS="function" >asinh()</B ></A >, <A HREF="function.acos.html" ><B CLASS="function" >acos()</B ></A >, and <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" >Înapoi</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Acasã</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.asinh.html" ACCESSKEY="N" >Înainte</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" >Sus</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >asinh</TD ></TR ></TABLE ></DIV ></BODY ></HTML >