ACOSH
Section: Linux Programmer's Manual (3)
Updated: 2008-08-05
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NAME
acosh, acoshf, acoshl - inverse hyperbolic cosine function
SYNOPSIS
#include <math.h>
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
acosh():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or
cc -std=c99
acoshf(),
acoshl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or
cc -std=c99
DESCRIPTION
The
acosh()
function calculates the inverse hyperbolic cosine of
x; that is the value whose hyperbolic cosine is x.
RETURN VALUE
On success, these functions return the inverse hyperbolic cosine of
x.
If
x
is a NaN, a NaN is returned.
If
x
is +1, +0 is returned.
If
x
is positive infinity, positive infinity is returned.
If
x
is less than 1,
a domain error occurs,
and the functions return a NaN.
ERRORS
See
math_error(7)
for information on how to determine whether an error has occurred
when calling these functions.
The following errors can occur:
- Domain error: x is less than 1
-
errno
is set to
EDOM.
An invalid floating-point exception
(FE_INVALID)
is raised.
CONFORMING TO
C99, POSIX.1-2001.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
SEE ALSO
asinh(3),
atanh(3),
cacosh(3),
cosh(3),
sinh(3),
tanh(3)
COLOPHON
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A description of the project,
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can be found at
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