#include <bits/stdc++.h>
using namespace std;
int n, l, v1, v2, k;
const double eps = 1e-11;
double check(double x, double &t) {
  t = 0;
  int nn = n;
  double nw = 0, tt;
  bool fl = 0;
  while (nn > 0) {
    nn -= k;
    if (!fl) {
      tt = (x - nw) / v2;
      t += tt;
      nw += tt * v1;
    } else {
      tt = (x - nw) / (v2 - v1);
      t += tt;
      nw += tt * v1;
      x += tt * v1;
    }
    if (nn <= 0) break;
    double t2 = (x - nw) / (v1 + v2);
    t += t2;
    nw += t2 * v1;
    x += t2 * v1;
    fl = 1;
  }
  return x;
}
int main() {
  scanf("%d%d%d%d%d", &n, &l, &v1, &v2, &k);
  if (v1 >= v2) {
    printf("%.10f\n", (double)l / v1);
    return 0;
  }
  double ll = 0, rr = l;
  double t = 0;
  for (int i = 0; i < 100; ++i) {
    double md = (ll + rr) / 2.0;
    if (check(md, t) < l + eps) {
      ll = md;
    } else {
      rr = md;
    }
  }
  check(ll, t);
  printf("%.10f\n", t);
  return 0;
}
