#include <stdio.h>
#include <math.h>
/*
set logscale x
set logscale y
plot "richard.dat" using 1:3 pt 5 ps 2,x**6 lc 0
*/
double f(double x){
    return sqrt(x);
}
double df(double x){
    return 1/(2*sqrt(x));
}
double adf(double x,double h){
    return (f(x+h)-f(x-h))/(2*h);
}
double radf(double x,double h){
    return 4.0/3*adf(x,h/2)-1.0/3*adf(x,h);
}
double r2adf(double x,double h){
    return (16*radf(x,h/2)-radf(x,h))/15;
}
double Eh(double x,double h){
    return fabs(r2adf(x,h)-df(x));
}
int main(){
    double h=1;
    for(int i=0;i<20;i++){
        printf("%g %22.15e %22.15e\n",
            h,adf(2,h),Eh(2,h));
        h/=2;
    }
    return 0;
}