#include <bits/stdc++.h>
using namespace std;
int n, k;
double l, v1, v2;
bool ok(double t) {
  int run = n / k + bool(n % k);
  double dist = l;
  for (int i = 0; i != run; i++) {
    if (dist < t * v1) return true;
    if (i == run - 1) {
      if (dist < t * v2)
        return true;
      else
        return false;
    }
    double dt = (dist - v1 * t) / (v2 - v1);
    double d = dist - v1 * t;
    double dti = d / (v1 + v2);
    t -= dt;
    dist -= v1 * dt;
    dist -= dti * v1;
    t -= dti;
  }
}
int main() {
  scanf("%d%lf%lf%lf%d", &n, &l, &v1, &v2, &k);
  double lb = l / v2;
  double ub = l / v1;
  while (lb + 1e-7 < ub) {
    double mid = (lb + ub) / 2;
    if (ok(mid))
      ub = mid;
    else
      lb = mid;
  }
  printf("%.10f\n", lb);
  return 0;
}
