1.\" Copyright (c) 1991 The Regents of the University of California.
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
--- 12 unchanged lines hidden (view full) ---
21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26.\" SUCH DAMAGE.
27.\"
28.\" from: @(#)atan.3 5.1 (Berkeley) 5/2/91
29.\" $FreeBSD: head/lib/msun/man/atan.3 165906 2007-01-09 01:02:06Z imp $
30.\"
31.Dd May 2, 1991
32.Dt ATAN 3
33.Os
34.Sh NAME
35.Nm atan ,
36.Nm atanf
37.Nd arc tangent functions of one variable
38.Sh LIBRARY
39.Lb libm
40.Sh SYNOPSIS
41.In math.h
42.Ft double
43.Fn atan "double x"
44.Ft float
45.Fn atanf "float x"
46.Sh DESCRIPTION
47The
48.Fn atan
49and the
50.Fn atanf
51functions compute the principal value of the arc tangent of
52.Fa x .
53For a discussion of error due to roundoff, see
54.Xr math 3 .
55.Sh RETURN VALUES
56The
57.Fn atan
58and the
59.Fn atanf
60function returns the arc tangent in the range
61.Bk -words
62.Bq -\*(Pi/2 , +\*(Pi/2
63.Ek
64radians.
65.Sh SEE ALSO
66.Xr acos 3 ,
67.Xr asin 3 ,
68.Xr atan2 3 ,
69.Xr cos 3 ,
70.Xr cosh 3 ,
71.Xr math 3 ,
72.Xr sin 3 ,
73.Xr sinh 3 ,
74.Xr tan 3 ,
75.Xr tanh 3
76.Sh STANDARDS
77The
78.Fn atan
79function conforms to
80.St -isoC .
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
--- 12 unchanged lines hidden (view full) ---
21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26.\" SUCH DAMAGE.
27.\"
28.\" from: @(#)atan.3 5.1 (Berkeley) 5/2/91
29.\" $FreeBSD: head/lib/msun/man/atan.3 165906 2007-01-09 01:02:06Z imp $
30.\"
31.Dd May 2, 1991
32.Dt ATAN 3
33.Os
34.Sh NAME
35.Nm atan ,
36.Nm atanf
37.Nd arc tangent functions of one variable
38.Sh LIBRARY
39.Lb libm
40.Sh SYNOPSIS
41.In math.h
42.Ft double
43.Fn atan "double x"
44.Ft float
45.Fn atanf "float x"
46.Sh DESCRIPTION
47The
48.Fn atan
49and the
50.Fn atanf
51functions compute the principal value of the arc tangent of
52.Fa x .
53For a discussion of error due to roundoff, see
54.Xr math 3 .
55.Sh RETURN VALUES
56The
57.Fn atan
58and the
59.Fn atanf
60function returns the arc tangent in the range
61.Bk -words
62.Bq -\*(Pi/2 , +\*(Pi/2
63.Ek
64radians.
65.Sh SEE ALSO
66.Xr acos 3 ,
67.Xr asin 3 ,
68.Xr atan2 3 ,
69.Xr cos 3 ,
70.Xr cosh 3 ,
71.Xr math 3 ,
72.Xr sin 3 ,
73.Xr sinh 3 ,
74.Xr tan 3 ,
75.Xr tanh 3
76.Sh STANDARDS
77The
78.Fn atan
79function conforms to
80.St -isoC .