#include <bits/stdc++.h>
using namespace std;
double eps = 1e-12;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const double PI = acos(-1.0);
const int MAXN = 1;
double l, v1, v2;
int n, k;
bool Judge(double m) {
  double t = (l - m * v1) / (v2 - v1);
  if (t < 0) return false;
  double pos = 0, lim = 0;
  int sum = n;
  while (sum > 0) {
    sum -= k;
    lim = pos + v2 * t;
    pos += 2 * v2 * v1 / (v2 + v1) * t;
  }
  if (lim <= l) return true;
  return false;
}
int main(int argc, char const *argv[]) {
  cin >> n >> l >> v1 >> v2 >> k;
  double lb = l / v2 - eps, ub = l / v1 + eps;
  for (int c = 1; c <= 300; ++c) {
    double m = (lb + ub) / 2.0;
    if (Judge(m))
      ub = m;
    else
      lb = m;
  }
  printf("%.12f\n", ub);
  return 0;
}
