#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  long long a = n / k;
  if (a * k < n) a++;
  double x = l * (a / (v2 - v1) + (a - 1) / (v2 + v1)) /
             (v2 * (a / (v2 - v1) - (a - 1) / (v2 + v1)));
  printf("%.10f", x);
}
