#include <bits/stdc++.h>
using namespace std;
int i, i0, n, m, k;
double l, v1, v2;
int main() {
  scanf("%d %lf %lf %lf %d", &m, &l, &v1, &v2, &k);
  double L = l / v2 - 1e-6, R = l / v1 + 1e-6;
  while (L + 1e-9 < R) {
    double mid = (L + R) / 2;
    double t = 0;
    n = m;
    while (t < mid) {
      n -= k;
      double r = ((t - mid + (l - t * v1) / v2) / (v1 - v2)) * v1 * v2;
      t += (l - t * v1 - r) / v2;
      if (n <= 0) break;
      t += (l - r - t * v1) / (v1 + v2);
    }
    if (t <= mid)
      R = mid;
    else
      L = mid + 1e-6;
  }
  printf("%.10f\n", R);
  return 0;
}
