xref: /freebsd/lib/msun/man/atanh.3 (revision 13014ca04aad1931d41958b56f71a2c65b9a7a2c)
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28.\"     from: @(#)atanh.3	5.2 (Berkeley) 5/6/91
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31.Dd January 14, 2005
32.Dt ATANH 3
33.Os
34.Sh NAME
35.Nm atanh ,
36.Nm atanhf
37.Nd inverse hyperbolic tangent functions
38.Sh LIBRARY
39.Lb libm
40.Sh SYNOPSIS
41.In math.h
42.Ft double
43.Fn atanh "double x"
44.Ft float
45.Fn atanhf "float x"
46.Sh DESCRIPTION
47The
48.Fn atanh
49and the
50.Fn atanhf
51functions compute the inverse hyperbolic tangent
52of the real
53argument
54.Ar x .
55For a discussion of error due to roundoff, see
56.Xr math 3 .
57.Sh RETURN VALUES
58The
59.Fn atanh
60and the
61.Fn atanhf
62functions
63return the inverse hyperbolic tangent of
64.Ar x
65if successful.
66If the argument has absolute value 1, a divide-by-zero exception
67is raised and an infinity is returned.
68If
69.Ar |x|
70> 1, an invalid exception is raised and an \*(Na is returned.
71.Sh SEE ALSO
72.Xr acosh 3 ,
73.Xr asinh 3 ,
74.Xr exp 3 ,
75.Xr fenv 3 ,
76.Xr math 3
77.Sh HISTORY
78The
79.Fn atanh
80function appeared in
81.Bx 4.3 .
82