ACOSH(3) Linux Programmer s Manual ACOSH(3)

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.

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)

2002-07-25 ACOSH(3)