#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, l, v1, v2, k, num;
  cin >> n >> l >> v1 >> v2 >> k;
  long double d, h, t, ride, wait, all, wwait;
  d = (l + 0.0) / v2;
  h = (l + 0.0) / v1;
  for (int i = 0; i < 50; i++) {
    t = (d + h) / 2;
    ride = (t * v1 * v2 - l * v2) / (v1 - v2);
    num = ceil((n + 0.0) / k);
    wait = (ride * (v2 - v1)) / v2;
    wwait = (wait * v2) / (v2 + v1);
    all = num * ride - (num - 1) * wwait;
    if (all > l)
      d = t;
    else
      h = t;
  }
  cout << setprecision(10) << t;
}
