classwork1

#include <iostream>
using namespace std;
#include <algorithm>
#include <vector>

int main()
{
    double pi = 3.1415926535;
    double P = 1.0;
    for (int i = 1; i <= 9000000; ++i) {
        P *= (double)(((double)i * (double)i * 4.0) / (4.0 * (double)i * (double)i - 1.0));
    }
    cout << "\n";
    cout << P << "\n";
    cout << pi / 2.0 << "\n";
}

/*
$ /c/projects/B.exe line_approx.txt
line_approx.txt  0.262479 0  0.873039 0
*/