xref: /freebsd/lib/msun/man/acosh.3 (revision c96ae1968a6ab7056427a739bce81bf07447c2d4)
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28.\"     from: @(#)acosh.3	5.2 (Berkeley) 5/6/91
29.\" $FreeBSD$
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31.Dd January 14, 2005
32.Dt ACOSH 3
33.Os
34.Sh NAME
35.Nm acosh ,
36.Nm acoshf
37.Nd inverse hyperbolic cosine functions
38.Sh LIBRARY
39.Lb libm
40.Sh SYNOPSIS
41.In math.h
42.Ft double
43.Fn acosh "double x"
44.Ft float
45.Fn acoshf "float x"
46.Sh DESCRIPTION
47The
48.Fn acosh
49and the
50.Fn acoshf
51functions compute the inverse hyperbolic cosine
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 acosh
60and the
61.Fn acoshf
62functions
63return the inverse hyperbolic cosine of
64.Ar x .
65If the argument is less than 1,
66.Fn acosh
67raises an invalid exception and returns an \*(Na.
68.Sh SEE ALSO
69.Xr asinh 3 ,
70.Xr atanh 3 ,
71.Xr exp 3 ,
72.Xr fenv 3 ,
73.Xr math 3
74.Sh HISTORY
75The
76.Fn acosh
77function appeared in
78.Bx 4.3 .
79