#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  double l, v1, v2;
  cin >> n >> l >> v1 >> v2 >> k;
  int nk = (n + k - 1) / k;
  double time = 2000000000;
  double delta = 1000000000;
  for (int i = 0; i < 500; i++) {
    if (delta == 0) break;
    double time_test = time - delta;
    double len_left = l - time_test * v1;
    if (len_left <= 0) {
      time -= delta;
      continue;
    }
    double time_f = time_test / (nk + (nk - 1) * (v2 - v1) / (v1 + v2));
    len_left -= time_f * (v2 - v1);
    if (len_left <= 0) {
      time -= delta;
      continue;
    }
    delta /= 2;
  }
  printf("%.10llf", time);
  return 0;
}
