/* Sneaky square root (C) 1997 by D. Corbit */
static long double const val28 = 28.0e0L;
static long double const val70 = 70.0e0L;
static long double const val6 = 6.0e0L;
static long double const valOneEighth = 0.125e0L;
static long double const valOneHalf = 0.5e0L;

long double     SqrtAB07(long double x, long double c)
{
    long double     x2 = x * x;
    long double     x4 = x2 * x2;
    long double     x8 = x4 * x4;
    long double     c2 = c * c;
    long double     c4 = c2 * c2;
    long double     ans0 =
    (val28 * (x2 * c * (x4 + c2)) + (val70 * c2 + x4) * x4 + c2 * c2) /
    (x * (x2 + c) * (x4 + val6 * x2 * c + c2)) * valOneEighth;
    long double     ans1 = c / ans0;
    return (ans0 + ans1) * valOneHalf;
}
#ifdef TEST
#include <stdio.h>
int             main(void)
{
    long double     c = 2.0e0L;
    long double     guess = 1.2e0L;
    guess = SqrtAB07(guess, c);
    printf("Square root of %Lg is estimated at\n %.18Le after 1 iteration.\n",
           c, guess);
    return 0;
}
#endif