#include <bits/stdc++.h>
using namespace std;
int n, l, v1, v2, k;
bool work(double tot) {
  int rem = n;
  double pos = 0.0;
  double time = 0.0;
  double lp = 0.0;
  while (rem > 0 && pos < l) {
    rem -= k;
    double dttt = (lp - pos) / (v1 + v2);
    time += dttt;
    pos += v1 * dttt;
    double d = (tot - ((double)l) / v1 + pos / v1 - time) * (double)v1 * v2 /
               (v1 - v2);
    double dt = d / v2;
    lp = pos + d;
    pos += dt * v1;
    time += dt;
  }
  return time <= tot;
}
int main() {
  scanf("%d%d%d%d%d", &n, &l, &v1, &v2, &k);
  double lo = (double)l / v2, hi = (double)l / v1;
  while (hi - lo > 5e-7) {
    double mid = (hi + lo) / 2;
    if (work(mid))
      hi = mid;
    else
      lo = mid;
  }
  printf("%.7f\n", (hi + lo) / 2);
}
