#include <stdio.h>

#define REAL float

int main(void){
  REAL x,y,z,h;
  printf ("    Step       Numerical            Analytical           Absolute Error\n");
  h = (REAL) 0.1;
  x = (REAL) 1.23456789;
  while (h > 1.0e-15){
    y = ((x+h)*(x+h)*(x+h) - x*x*x)/h;
    z = 3.0 * x * x;
    printf ("%10.2e %20.12e %20.12e %20.12e \n",h,y,z,y-z);
    h = h * 0.1;
  }
  return 0;
}


    //    y = ((x+h)*(x+h)*(x+h) - (x-h)*(x-h)*(x-h))/(2.0*h);