#include <bits/stdc++.h>
using namespace std;
const long double PI = 3.1415926535897932384626433832795;
template <typename S, typename T>
ostream& operator<<(ostream& out, pair<S, T> const& p) {
  out << '(' << p.first << ", " << p.second << ')';
  return out;
}
template <typename T>
ostream& operator<<(ostream& out, vector<T> const& v) {
  int l = v.size();
  for (int i = 0; i < l - 1; i++) out << v[i] << ' ';
  if (l > 0) out << v[l - 1];
  return out;
}
void tr() { cout << endl; }
template <typename S, typename... Strings>
void tr(S x, const Strings&... rest) {
  cout << x << ' ';
  tr(rest...);
}
int n, k;
double l, v1, v2;
bool f(double T) {
  int s = n;
  double d1 = 0, d2 = 0;
  while (s > 0) {
    double x = l - d1;
    double t = (x - v1 * T) / (v2 - v1);
    if (t > T) return false;
    T -= t;
    s -= k;
    if (s <= 0) return true;
    d2 = d1 + v2 * t;
    d1 += v1 * t;
    t = (d2 - d1) / (v1 + v2);
    if (t > T) return false;
    T -= t;
    d1 = d2 = d1 + v1 * t;
  }
  return true;
}
int main() {
  cin >> n >> l >> v1 >> v2 >> k;
  double lo = 0, hi = l / v1, mid;
  for (int i = 0; i < 100; i++) {
    mid = (lo + hi) / 2;
    if (f(mid))
      hi = mid;
    else
      lo = mid;
  }
  cout << fixed << setprecision(20) << hi << endl;
  return 0;
}
