#include <bits/stdc++.h>
using namespace std;
int main() {
  long long T, n;
  cin >> T;
  while (T--) {
    cin >> n;
    double x = (3.141592653589793238) / (2 * n);
    cout << fixed << setprecision(10) << cos(x) / sin(x) << "\n";
  }
  return 0;
}
