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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)):
Feature Test Macro Requirements for glibc (see
feature_test_macros (7)):
acosh () acoshf () acoshl (): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _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. If x is less than 1.0, acosh () returns not-a-number (NaN) and errno is
set.
ERRORS
EDOM x is out of range.
CONFORMING TO
SVr4, POSIX.1-2001, 4.3BSD, C89. The float and
long double variants are C99 requirements.
SEE ALSO
asinh (3) atanh (3)
cacosh (3) cosh (3) sinh (3) tanh (3)
