#include <bits/stdc++.h>
using namespace std;
int n;
double l, v1, v2;
int k;
double judge(double t) {
  double mustT = (l - v1 * t) / (v2 - v1);
  double mustCNT = (n - 1) / k + 1;
  return mustT * mustCNT + (mustCNT - 1) * ((v2 - v1) * mustT / (v1 + v2));
}
int main() {
  scanf("%d%lf%lf%lf%d", &n, &l, &v1, &v2, &k);
  double L = 0;
  double R = l / v1;
  for (int i = 1; i <= 300; i++) {
    double mid = (L + R) / 2;
    if (judge(mid) <= mid)
      R = mid;
    else
      L = mid;
  }
  printf("%.10f\n", L);
  return 0;
}
