#include <bits/stdc++.h>
using namespace std;
double DEG_to_RAD(double d) { return d * acos(-1.0) / 180.0; }
auto main() -> int {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int tc;
  cin >> tc;
  cout << fixed << setprecision(8);
  while (tc--) {
    int n;
    cin >> n;
    double outangle = 180.0 * (2 * n - 2) / (2 * n);
    double inangle = 360.0 / (2 * n);
    double half_in_angle = 360.0 / (4 * n);
    double inside = 0.5 / sin(DEG_to_RAD(half_in_angle));
    double hi = inside * 2,
           lo = 0.5 / tan(DEG_to_RAD(half_in_angle)) * 2 - 0.01;
    while (lo + 1e-13 < hi) {
      double mid = (lo + hi) / 2;
      double shift = acos(mid / (2 * inside));
      double new_height = sin(DEG_to_RAD(outangle / 2) + shift) * 2 * inside;
      if (new_height <= mid)
        hi = mid;
      else
        lo = mid;
    }
    cout << hi << '\n';
  }
  return 0;
}
