Manual Pages  — ACOSH

acosh, acoshf, acoshl – inverse hyperbolic cosine functions

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES SEE ALSO HISTORY

Math Library (libm, -lm)

#include <math.h>

double
acosh(double x);

float
acoshf(float x);

long double
acoshl(long double x);

These functions return the inverse hyperbolic cosine of x. If the argument is less than 1, acosh() raises an invalid exception and returns an NaN.

The acosh(), acoshf(), and acoshl() functions appeared in BSD 4.3, FreeBSD 2.0, and FreeBSD 10.0, respectively.