ACOSH(3)                  OpenBSD 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 acoshf() functions compute the inverse hyperbolic cosine
     of the real argument x.

RETURN VALUES
     If x is less than one, acosh(x) and acoshf(x) returns NaN and sets the
     global variable errno to EDOM.

SEE ALSO
     asinh(3),  atanh(3),  exp(3),  infnan(3),  math(3)

HISTORY
     The acosh() function appeared in 4.3BSD.

OpenBSD 2.6                       May 6, 1991                                1