#include <bits/stdc++.h>
using namespace std;
int n, L, v1, v2, k;
bool check(double t) {
  double pos = 0;
  for (int i = 0; i + k < n; i += k) {
    double t1 = max((L - pos - v1 * t) / (v2 - v1), 0.0);
    double t2 = (t1 * v2 - t1 * v1) / (v1 + v2);
    pos += (t1 + t2) * v1;
    t -= t1 + t2;
  }
  return pos + t * v2 > L;
}
int main() {
  cin >> n >> L >> v1 >> v2 >> k;
  if (n <= k) {
    printf("%.9f\n", (double)L / v2);
    return 0;
  }
  double l = 0, r = L;
  for (int i = 0; i < 100; ++i) {
    double t = (l + r) / 2;
    if (check(t))
      r = t;
    else
      l = t;
  }
  printf("%.9f\n", (l + r) * 0.5);
  return 0;
}
