#include <bits/stdc++.h>

using namespace std;


double f(double x)
{
    return 3.0 * cos(x) - x;
}

double dfdx(double x)
{
    return (- 3.0 * sin(x) - 1);
}


int main()
{
    cout.precision(20);

    double eps;

    cout << "Get me your precision: ";

    cin >> eps;

        cout << '\n';

        double x = 0;

        int iter = 1;

    while (abs(f(x) - 0.) > eps)
    {
            assert(abs(dfdx(x)) > 1e-9);

            x = x - f(x) / dfdx(x);

        cout << "On step " << iter << " value is " << x << ".\n";

        cout << "Residual is " << -f(x) << ".\n";

        cout << " * * * * \n";

        iter++;

    }

        cout << "(x, f(x) = (" << x <<  ", " << f(x) << ")\n";

        return 0;
}