#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long double pi = acos(-1);
const int MOD = 1e9 + 7;
int n, l, v1, v2, k;
double eps = 1e-9;
bool simula(long double T) {
  long double fim = l;
  long double p = n;
  long double delt = v2 - v1;
  long double sum = v2 + v1;
  while (p > 0) {
    p -= k;
    long double num = fim - 1.0 * T * v1;
    long double t0 = num / delt;
    T -= t0;
    fim -= t0 * v1;
    if (p > 0) {
      long double te = ((v2 * t0) - v1 * t0) / sum;
      long double x = 1.0 * v1 * te;
      T -= te;
      fim -= x;
    }
  }
  return (T > 0);
}
long double bb(long double b, long double e) {
  long double m = (b + e) / 2.0;
  if (e - b < eps) return b;
  if (simula(m)) return bb(b, m);
  return bb(m, e);
}
int main() {
  cin >> n >> l >> v1 >> v2 >> k;
  cout << fixed << setprecision(10) << bb(0, 1000000000) << "\n";
  return 0;
}
