#include <bits/stdc++.h>
using namespace std;
const long long inf = 0x3f3f3f3f3f3f3f3f;
int A[100002];
double v1, v2, X;
int k;
double solve(int n, double l, double T) {
  if (n <= k) {
    return l / v2;
  }
  return solve(n - k, l - X * v1 * T, T) + T * X;
}
int main() {
  int n;
  double L;
  double T = 0.001;
  while (cin >> n >> L >> v1 >> v2 >> k) {
    queue<double> que;
    X = 2 * v2 / (v1 + v2);
    double l = 0, r = L / v2;
    double ans = 1e9;
    for (int ii = 0; ii < 60; ii++) {
      double mid = 0.5 * (l + r);
      double midmid = 0.5 * (mid + r);
      double res = max(solve(n, L, mid), (L - mid * v2) / v1 + mid);
      double ret = max(solve(n, L, midmid), (L - midmid * v2) / v1 + midmid);
      if (res <= ret) {
        r = midmid;
        ans = res;
      } else {
        l = mid;
        ans = ret;
      }
    }
    printf("%.10f\n", ans);
  }
  return 0;
}
