acosh

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);

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.  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)