relibc_openlibm/man/atan.3

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.\"     from: @(#)atan.3	5.1 (Berkeley) 5/2/91
.\" $FreeBSD: src/lib/msun/man/atan.3,v 1.12 2008/07/31 22:41:26 das Exp $
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.Dd July 31, 2008
.Dt ATAN 3
.Os
.Sh NAME
.Nm atan ,
.Nm atanf ,
.Nm atanl
.Nd arc tangent functions of one variable
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn atan "double x"
.Ft float
.Fn atanf "float x"
.Ft long double
.Fn atanl "long double x"
.Sh DESCRIPTION
The
.Fn atan ,
.Fn atanf ,
and
.Fn atanl
functions compute the principal value of the arc tangent of
.Fa x .
.Sh RETURN VALUES
These functions return the arc tangent in the range
.Bk -words
.Bq -\*(Pi/2 , +\*(Pi/2
.Ek
radians.
.Sh SEE ALSO
.Xr acos 3 ,
.Xr asin 3 ,
.Xr atan2 3 ,
.Xr cos 3 ,
.Xr cosh 3 ,
.Xr math 3 ,
.Xr sin 3 ,
.Xr sinh 3 ,
.Xr tan 3 ,
.Xr tanh 3
.Sh STANDARDS
The
.Fn atan ,
.Fn atanf ,
and
.Fn atanl
functions conform to
.St -isoC-99 .