#include <bits/stdc++.h>
using namespace std;
long long n, l, v1, v2, k;
const double EPS = 1e-7;
bool ok(double t) {
  long long m = n;
  double x = 0;
  double t0 = 0;
  while (m > 0) {
    double left_time = t - t0;
    if (left_time * v1 >= (l - x)) return true;
    if (left_time < 0) return false;
    int g = min(m, k);
    m -= g;
    double y = (v2 * l - v1 * x - left_time * v1 * v2) / (v2 - v1);
    if (y > l || y < x) return false;
    double u = 2 * (y - x) / (v1 + v2);
    if (m == 0) u = (y - x) / v2 + (l - y) / v1;
    x += v1 * u;
    t0 += u;
  }
  if (t0 - t > EPS) return false;
  return true;
}
int main() {
  scanf("%lld%lld%lld%lld%lld", &n, &l, &v1, &v2, &k);
  double lo = 0, hi = l / (double)v1;
  for (int i = 0; i < 300; i++) {
    double mid = (lo + hi) / 2;
    if (ok(mid))
      hi = mid;
    else
      lo = mid;
  }
  printf("%.10f", lo);
}
