#include <bits/stdc++.h>
using namespace std;
double l, v1, v2;
int main() {
  int n, d, k;
  cin >> n >> l >> v1 >> v2 >> d;
  k = n / d;
  if (n % d) k++;
  double L = l / v2, R = l / v1;
  for (int i = 1; i <= 1000000; i++) {
    double M = (R + L) / 2;
    if (M * v2 * (v2 - v1) >=
        (2 * k - 1) * v2 * (l - v1 * M) - v1 * (M * v2 - l))
      R = M;
    else
      L = M;
  }
  printf("%.12lf\n", L);
  return 0;
}
