#include <bits/stdc++.h>
void rd(int &x) {
  x = 0;
  int f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch <= '9' && ch >= '0') x = x * 10 + ch - '0', ch = getchar();
  x *= f;
}
void lrd(long long &x) {
  x = 0;
  int f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch <= '9' && ch >= '0') x = x * 10 + ch - '0', ch = getchar();
  x *= f;
}
const int INF = 1e9;
const long long LINF = 1e18;
using namespace std;
int T, n;
int main() {
  rd(T);
  while (T--) {
    rd(n);
    double tmp = 1.0 / (1 - cos(acos(-1) / n));
    printf("%.9lf\n", sqrt(tmp * 2) * cos(acos(-1) / n / 4));
  }
  return 0;
}
