NAME    [Toc]    [Back]

       acosh - inverse hyperbolic cosine function

SYNOPSIS    [Toc]    [Back]

       #include <math.h>

       double acosh(double x);

DESCRIPTION    [Toc]    [Back]

       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    [Toc]    [Back]

       EDOM   x is out of range.

CONFORMING TO    [Toc]    [Back]

       SVID 3, POSIX, BSD 4.3, ISO 9899

SEE ALSO    [Toc]    [Back]

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



				  1993-06-13			      ACOSH(3)