#include <bits/stdc++.h>
using namespace std;
int n, l, v1, v2, k;
bool check(double t) {
  double time = 0;
  int remn = n;
  double last = 0;
  double bus = 0;
  while (remn > 0) {
    double pos = time * v1;
    if ((t - time) * v1 + pos >= l) return true;
    double dist = (bus - pos) * v1 / double(v1 + v2);
    pos += dist;
    time += dist / v1;
    double rem = l - pos;
    double a = 0, b = t - time, m;
    for (int it = 0; it < 90; ++it) {
      m = (a + b) / 2;
      if ((rem - m * v2) / v1 <= t - time - m)
        b = m;
      else
        a = m;
    }
    if ((rem - m * v2) / v1 > t - time - m + 1e-9) return false;
    time += m;
    remn -= k;
    last = max(last, time + (rem - m * v2) / v1);
    bus = pos + m * v2;
  }
  return true;
}
int main() {
  scanf("%d%d%d%d%d", &n, &l, &v1, &v2, &k);
  double a = 0, b = 1e9 + 10, m;
  for (int it = 0; it < 90; ++it) {
    m = (a + b) / 2;
    if (check(m))
      b = m;
    else
      a = m;
  }
  printf("%.12lf\n", m);
  return 0;
}
