#include <bits/stdc++.h>
using namespace std;
int main() {
  double l, v1, v2;
  int n, k;
  cin >> n >> l >> v1 >> v2 >> k;
  if (k >= n) {
    cout << 1.0 * l / v2 << endl;
    return 0;
  }
  int T = (n - 1) / k;
  double t = 1.0 * l / (2.0 * v1 * v2 * T / (v1 + v2) + v2);
  cout << fixed << setprecision(9);
  cout << t + (l - t * v2) / v1 << endl;
  return 0;
}
