#include <bits/stdc++.h>   using namespace std;   long long n, l, v1, v2, k;   int main() {     cin >> n >> l >> v1 >> v2 >> k;     long long g = (n + k - 1) / k;     double le = 0, ri = l / (double)v1;     while ((ri - le) >= 5e-7) {       double mid = (le + ri) / 2;       double t = 0;       for (int i = 1; i <= g; i++) {         double x = ((double)l - v1 * mid) / (v2 - v1);         t += x;         if (i != g) {           double y = x * (v2 - v1) / (v1 + v2);           t += y;         }       }       if (mid > t)         ri = mid;       else         le = mid;     }     cout << setprecision(9) << le << endl;     return 0;   }   