#include <bits/stdc++.h>
const int N = 3 * 1e5 + 5;
const long long MOD = 998244353;
const long long inf = 1e18;
using namespace std;
long long int MAXN = 100001;
long long int spf[100001];
long long int modpow(long long int x, long long int n) {
  long long int res = 1;
  while (n > 0) {
    if (n & 1) res = res * x % MOD;
    x = x * x % MOD;
    n >>= 1;
  }
  return res;
}
long long int modFact(long long int n, long long int p) {
  if (n >= p) return 0;
  long long int result = 1;
  for (long long int i = 1; i <= n; i++) result = (result * i) % p;
  return result;
}
bool isPrime(int x) {
  if (x % 2 == 0) return 0;
  for (int i = 3; i <= sqrt(x); i += 2) {
    if (x % i == 0) return 0;
  }
  return 1;
}
float polydiagonal(float n, float a) {
  if (a < 0 && n < 0) return -1;
  return 2 * a * sin((((n - 2) * 180) / (2 * n)) * 3.14159 / 180);
}
void solve() {
  int n;
  cin >> n;
  if (n == 2) {
    cout << 1.0000000 << "\n";
    return;
  }
  cout << fixed << setprecision(8)
       << 1.0 / (sin((180.0 / (2 * n)) * (3.14159 / 180))) << "\n";
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  cerr << "Time : " << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC
       << "ms\n";
}
