#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, l, k;
  double v1, v2;
  int ret;
  double t1, t2;
  scanf("%d%d%lf%lf%d", &n, &l, &v1, &v2, &k);
  ret = (n - 1) / k;
  t1 = 1.0 * 2 * l * ret / (1.0 * ((1 + 2 * ret) * v1 + v2));
  t2 = 1.0 * (l - v1 * t1) / (1.0 * v2);
  printf("%.8lf", t1 + t2);
  return 0;
}
