<HTML ><HEAD ><TITLE >Asin</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.44"><LINK REL="HOME" TITLE="PHP Manual" HREF="manual.html"><LINK REL="UP" TITLE="Mathematical functions" HREF="ref.math.html"><LINK REL="PREVIOUS" TITLE="Acos" HREF="function.acos.html"><LINK REL="NEXT" TITLE="Atan" HREF="function.atan.html"></HEAD ><BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.acos.html" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.atan.html" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.asin" >Asin</A ></H1 ><DIV CLASS="refnamediv" ><A NAME="AEN15526" ></A >Asin -- arc sine</DIV ><DIV CLASS="refsect1" ><A NAME="AEN15529" ></A ><H2 >Description</H2 ><DIV CLASS="funcsynopsis" ><P ></P ><CODE CLASS="FUNCDEF" >float asin</CODE >(float arg);<P ></P ></DIV ><P > Returns the arc sine of arg in radians.</P ><P > See also <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 WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.acos.html" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="manual.html" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.atan.html" >Next</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" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Atan</TD ></TR ></TABLE ></DIV ></BODY ></HTML >