The
acosh ();
and the
acoshf ();
functions compute the inverse hyperbolic cosine
of the real
argument
x
For a discussion of error due to roundoff, see
math(3).
RETURN VALUES
The
acosh ();
and the
acoshf ();
functions
return the inverse hyperbolic cosine of
x
If the argument is less than 1,
acosh ();
raises an invalid exception and returns an .
