#include <bits/stdc++.h>
using namespace std;
int n, len, v1, v2, k, g;
bool check(double time) {
  double t2 = double(len - v1 * time) / (v2 - v1);
  if (t2 < 0) return true;
  double tb = (t2 * v2 - (t2)*v1) / (v1 + v2);
  double ttb = tb * (g - 1) + t2 * g;
  return ttb <= time;
}
int main() {
  scanf("%d%d%d%d%d", &n, &len, &v1, &v2, &k);
  g = ceil((n + 0.0) / k);
  double l = 0, r = 1e18;
  double ans = 1e18;
  for (int i = 0; i < 300; i++) {
    double mid = (l + r) / 2.0;
    if (check(mid)) {
      r = mid;
      ans = min(ans, mid);
    } else
      l = mid;
  }
  cout << setprecision(8) << fixed << ans << endl;
  return 0;
}
