#include <iostream>
#include <math.h>

using namespace std;

int main()
{
    double x = 3.0, y1, y, sum=0;
    cout << "***********************************************************************" << endl;
    cout << "y = ";
    for (int n = 1; n < 21; n++){
        y = 2 * 1/((2*n+1)*pow(x,(2*n+1)));
        sum += y;
        if (n < 20)
        {
            cout << y << " + ";
        }
        else if (n == 20)
        {
            cout << y << " = ";
        }
    }
    cout << sum << endl;
    cout << "***********************************************************************" << endl;
    y1 = log((x+1)/(x-1));
    cout << "x = " << x << " y = " << sum << " y1 = " << y1 << endl;
}