#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k;
  double l, v1, v2;
  cin >> n >> l >> v1 >> v2 >> k;
  double num = n / k + (bool)(n % k);
  double o = (num - 1) * (v2 - v1) / (v2 + v1) + num;
  double t = l / (o * v1 + v2 - v1);
  printf("%.13lf\n", (l - t * (v2 - v1)) / v1);
}
