#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, len, v1, v2, k, t = 0.0, l, r;
  cin >> n >> len >> v1 >> v2 >> k;
  int it = 500;
  l = len / v2, r = len / v1;
  while (it-- && l <= r) {
    double mid = (l + r) / 2.0, tt = 0.0;
    double nn = n, le = len;
    while (nn > 0 && tt < mid) {
      double x, t;
      if (tt + le / v1 <= mid) {
        tt += le / v1;
        break;
      }
      x = v1 * (mid - tt);
      x = v2 * (le - x);
      nn -= k;
      if (nn <= 0) {
        tt += le / v2;
        break;
      }
      x /= (v2 - v1);
      t = x / v2;
      t += (x - (v1 * t)) / (v1 + v2);
      le -= v1 * t;
      tt += t;
    }
    if (tt >= mid)
      l = mid;
    else
      r = mid;
  }
  cout << fixed << setprecision(10);
  cout << l << endl;
}
