#include <bits/stdc++.h>
using namespace std;
double l, t;
int T, L;
int n, k, v1, v2;
int main() {
  cin >> n >> L >> v1 >> v2 >> k;
  double lb(0), ub(1000000000.0F);
  while (((lb + 0.0000001F) <= ub) && (lb * 1.0000001F) <= ub) {
    double T = (lb + ub) / 2.0F;
    l = L;
    t = 0;
    bool ok = 1;
    for (int i = 0; i * k < n; i++) {
      double l2 = ((T - t) * v1 - l) * v2 / (v1 - v2);
      double tt = 2 * l2 / (v1 + v2 + 0.0F);
      if (l2 > l) ok = 0;
      t += tt;
      l -= tt * v1;
      if (l < 0) ok = 0;
    }
    if (ok) {
      ub = T;
    } else
      lb = T + 0.0000001F;
  }
  cout << setprecision(7) << fixed << lb << endl;
  return 0;
}
