#include <bits/stdc++.h>
using namespace std;
const long long N = 200005, INF = 2000000000000000000;
long long power(long long a, long long b, long long p) {
  if (a == 0) return 0;
  long long res = 1;
  a %= p;
  while (b > 0) {
    if (b & 1) res = (res * a) % p;
    b >>= 1;
    a = (a * a) % p;
  }
  return res;
}
vector<long long> prime;
bool is_composite[N];
void sieve(long long n) {
  memset(is_composite, false, sizeof(is_composite));
  for (long long i = 2; i < n; ++i) {
    if (!is_composite[i]) prime.push_back(i);
    for (long long j = 0; j < prime.size() && i * prime[j] < n; ++j) {
      is_composite[i * prime[j]] = true;
      if (i % prime[j] == 0) break;
    }
  }
}
void print(bool n) {
  if (n) {
    cout << "YES";
  } else {
    cout << "NO";
  }
}
long double pi = 2 * acos(0.0);
int32_t main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long T;
  cin >> T;
  while (T--) {
    long double n;
    cin >> n;
    n *= 2;
    long double ans = tan((pi * (n - 2)) / (2 * n));
    cout << setprecision(12);
    cout << ans << "\n";
  }
}
