NAME
acosh,
acoshf,
acoshl
—
inverse hyperbolic cosine function
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
acosh(
double
x);
float
acoshf(
float
x);
long double
acoshl(
long
double x);
DESCRIPTION
The
acosh(),
acoshf(), and
acoshl() functions compute the inverse hyperbolic cosine of
the real argument
x.
RETURN VALUES
If x is less than one,
acosh(
x),
acoshf(
x), and
acoshl(
x) return NaN and set the
global variable
errno to EDOM.
SEE ALSO
asinh(3),
atanh(3),
exp(3),
math(3)
STANDARDS
The
acosh() function conforms to
ISO/IEC
9899:1999 (“ISO C99”).
HISTORY
The
acosh() function appeared in
4.3BSD.