NAME
	IEEEDPAcos -- compute the arc cosine of a number

   SYNOPSIS
	  x   = IEEEDPAcos(  y  );
	d0/d1	           d0/d1

	double	x,y;

   FUNCTION
	Compute arc cosine of y in IEEE double precision

   INPUTS
	y - IEEE double precision floating point value

   RESULT
	x - IEEE double precision floating point value

   BUGS

   SEE ALSO
	IEEEDPCos(), IEEEDPAtan(), IEEEDPAsin()