ACOSH(3) BSD Programmer's Manual ACOSH(3)NAME
acosh, acoshf - inverse hyperbolic cosine functions
SYNOPSIS
#include <math.h>
double
acosh(double x);
float
acoshf(float x);
DESCRIPTION
The acosh() and the acoshf() functions compute the inverse hyperbolic co-
sine of the real argument x. For a discussion of error reporting, see
math(3).
ERRORS
If |x| < 1 then:
_IEEE_ The return value is NaN.
_POSIX_ Same as _IEEE_, and errno is also set to EDOM.
_XOPEN_ Same as _POSIX_, but errno is only set if matherr(3) returns 0.
The exception type is DOMAIN.
_SVID_ Same as _XOPEN_, and a message is printed to stderr if errno is
set.
SEE ALSOasinh(3), atanh(3), exp(3), math(3)HISTORY
The acosh() function appeared in 4.3BSD.
4.3 Berkeley Distribution February 17, 1998 1