#include <bits/stdc++.h>
using namespace std;

int main() {
  int T; cin >> T;
  vector<int> N(T); for(int i=0; i<T; i++) cin >> N[i];

  double c = 1.0 / (exp(1.0) * M_PI * M_PI);
  vector<double> A(T);
  for (int i=0; i<T; i++){
    A[i] = c * (exp(1.0) + 4*exp(cos(c / (2*N[i]))) + exp(cos(c / N[i]))) / 6.0;
    cout << A[i] << endl;
  }

}