xref: /freebsd/lib/msun/man/atan.3 (revision 75141cc9877bd4c86b39c602f68ae5dc205cefdb)

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.\"     from: @(#)atan.3	5.1 (Berkeley) 5/2/91
.\"	$FreeBSD$
.\"
.Dd May 2, 1991
.Dt ATAN 3
.Os
.Sh NAME
.Nm atan ,
.Nm atanf
.Nd arc tangent functions of one variable
.Sh SYNOPSIS
.Fd #include <math.h>
.Ft double
.Fn atan "double x"
.Ft float
.Fn atanf "float x"
.Sh DESCRIPTION
The
.Fn atan
and the
.Fn atanf
functions compute the principal value of the arc tangent of
.Fa x .
For a discussion of error due to roundoff, see
.Xr math 3 .
.Sh RETURN VALUES
The
.Fn atan
and the
.Fn atanf
function returns 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
function conforms to
.St -ansiC .