#include <bits/stdc++.h>
using namespace std;
const long double eps = 1e-8;
int N, L, v1, v2, K;
void load() { scanf("%d%d%d%d%d", &N, &L, &v1, &v2, &K); }
bool check(long double t) {
  long double curr = 0, pos = 0;
  for (int i = 0; i < N; i++) {
    long double tmp =
        max((L - pos - v1 * (t - curr)) / (v2 - v1), (long double)0);
    curr += tmp;
    pos += tmp * v2;
    if (i == N - 1) break;
    tmp = max(2 * (pos - curr * v1) / (v1 + v2), (long double)0);
    curr += tmp;
  }
  return curr < t + eps;
}
long double solve() {
  N = (N - 1) / K + 1;
  long double lo = 0, hi = L;
  for (int i = 0; i < 1000; i++) {
    long double mid = (lo + hi) / 2;
    if (check(mid))
      hi = mid;
    else
      lo = mid;
  }
  return lo;
}
int main() {
  load();
  printf("%.15lf\n", (double)solve());
  return 0;
}
