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





NAME
       acosh,  acoshf, acoshl - inverse hyperbolic cosine func-
       tion

SYNOPSIS
       #include <math.h>

       double acosh(double x);

       float acoshf(float x);

       long double acoshl(long 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-num-
       ber (NaN) and errno is set.

ERRORS
       EDOM   x is out of range.

CONFORMING TO
       SVID  3,  POSIX,  BSD 4.3, ISO 9899.  The float and long
       double variants are C99 requirements.

SEE ALSO
       asinh(3), atanh(3), cosh(3), sinh(3), tanh(3)



                           2002-07-25                  ACOSH(3)
