ACOSH(H)            Linux Programmer's Manual            ACOSH(H)



NAME
       acosh - inverse hyperbolic cosine function

SYNOPSIS
       #include <math.h>

       double acosh(double x);

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
       SVID 3, POSIX, BSD 4.3, ISO 9899

SEE ALSO
       asinh(h), atanh(h), cosh(h), sinh(h), tanh(h)



                            1993-06-13                   ACOSH(H)