#include <bits/stdc++.h>
using namespace std;
long long n, k, i, t;
double l, v1, v2;
long long check(double mid) {
  long long d = n, cur;
  double first = (v2 * l - mid * v1 * v2) / (v2 - v1),
         tim = (2 * first * (t - 1)) / (v1 + v2) + first / v2;
  return tim <= mid;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> l >> v1 >> v2 >> k;
  t = (n / k) + !!(n % k);
  double lo = 0, hi = 1e9, mid;
  cout << fixed << setprecision(10);
  for (i = 0; i < 80; ++i) {
    mid = (lo + hi) / 2;
    if (check(mid))
      hi = mid;
    else
      lo = mid;
  }
  cout << mid;
  return 0;
}
