#include <bits/stdc++.h>
using namespace std;
int n, k;
double d, v1, v2;
double check0(double e, double t) {
  if (e > v2 * t) return -1.0;
  double m, l = 0.0, r = e;
  for (int i = 0; i < 50; i++) {
    m = (l + r) / 2;
    if (m / v2 + (e - m) / v1 <= t)
      r = m;
    else
      l = m;
  }
  return l;
}
bool check(double t) {
  int m = (n + k - 1) / k;
  double e = d, cur;
  while (m--) {
    cur = check0(e, t);
    if (cur == -1.0) return 0;
    t -= cur / v2;
    e -= cur / v2 * v1;
    cur -= cur / v2 * v1;
    t -= cur / (v1 + v2);
    e -= cur / (v1 + v2) * v1;
  }
  return 1;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> d >> v1 >> v2 >> k;
  double l = 0.0, r = d / v1, m;
  for (int i = 0; i < 50; i++) {
    m = (l + r) / 2;
    if (check(m))
      r = m;
    else
      l = m;
  }
  cout << fixed << setprecision(8) << l;
}
