#include <bits/stdc++.h>
using namespace std;
const long double eps = 1e-8;
int n, k;
long double l, v1, v2;
bool ok(long double limit) {
  double current = 0, time = 0;
  for (int i = n; i > 0; i -= k) {
    long double pos = time * v1;
    long double back = (current - pos) / (v1 + v2);
    pos += v1 * back;
    time += back;
    if (time + (l - pos) / v2 > limit) return false;
    long double delta = ((limit - time) * v1 * v2 - (l - pos) * v2) / (v1 - v2);
    time += delta / v2;
    current = pos + delta;
  }
  return true;
}
int main() {
  cin >> n >> l >> v1 >> v2 >> k;
  long double low = l / v2;
  long double high = l / v1;
  while (low + eps < high) {
    long double mid = (low + high) / 2;
    if (!ok(mid))
      low = mid + eps;
    else
      high = mid;
  }
  cout << fixed << setprecision(10) << low;
  return 0;
}
