#include<bits/stdc++.h>
using namespace std;
 
#define NL '\n'
#define xx first
#define yy second
#define ll long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define sz(x) x.size()
#define all(x) (x).begin(), (x).end()
#define mem(a, b) memset(a, b, sizeof(a))
#define rep(i,a,b) for(ll i=(ll)a;i<(ll)b;++i)
#define async() ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)

#define pi acos(-1)
 
#define FayeValentine 
void dbg(){cerr<<NL;}template<typename H,typename... T> void dbg(H h,T... t){cerr<<' '<<h;dbg(t... );}
#ifdef  FayeValentine
#define debug(...) cerr<<"("<<#__VA_ARGS__<<"):",dbg(__VA_ARGS__)
#else
#define debug(...) 
#endif


void absinthe() {
	int n; cin >> n;
	double a = (360.00 / (double)(4.00*n));
	a *= (pi / 180.0);
	double r =  1.00/(sqrt(2-2*(cos(a))));
	cout << fixed << setprecision(9) << r << NL;
}
 
 
int main(){
  async();
  int __t = 1; cin >> __t;
  for(int __c = 1; __c <=__t; __c++) {
    //cout << "Case " << __c << ": "; 
    absinthe();
  }
}