#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  double n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  double low = 0, high = l / v1, mid;
  while (high - low > 1e-6) {
    mid = (low + high) / 2;
    double tonbus = (l - v1 * mid) / (v2 - v1);
    double twalk = mid - tonbus;
    double dbus = tonbus * (v2 - v1) / (v2 + v1);
    int rev = ceil(n / k - 1e-9) - 1;
    bool flag;
    if (rev * (tonbus + dbus) > twalk + 1e-11)
      flag = false;
    else
      flag = true;
    if (flag)
      high = mid;
    else
      low = mid;
  }
  cout << setprecision(10) << fixed << high;
  return 0;
}
