---

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
    double a, b, x, F;

    cout << "Enter a, b, x: ";
    cin >> a >> b >> x;

    double p = sqrt(a + b * x);
    double q = sqrt(a);

    F = (1.0 / q) * log((p - q) / (q * p + q));

    cout << "F = " << F << endl;

    return 0;
}

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
    double a, b, x, F;

    cout << "Enter a, b, x: ";
    cin >> a >> b >> x;

    double p = sqrt(a + b * x);
    double q = sqrt(a);

    F = (1.0 / q) * log((p - q) / (q * p + q));

    cout << "F = " << F << endl;

    return 0;
}