#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  double lo = 0;
  double hi = (l / v1);
  int grps = ceil(n / k);
  while (hi - lo > 1e-7) {
    double mid = ((double)lo + (double)hi) / 2;
    double x = (double)(l - v1 * mid) / (double)(v2 - v1);
    double y = ((double)x * (v2 - v1)) / (v2 + v1);
    x = (double)grps * x;
    y = ((double)grps - (double)1) * y;
    if ((double)x + (double)y > (double)mid)
      lo = mid;
    else
      hi = mid;
  }
  cout << fixed;
  cout << setprecision(7);
  cout << lo << endl;
  return 0;
}
