#include <bits/stdc++.h>
int main(void) {
  double time;
  double n, l, v1, v2, k;
  while (~scanf("%le %le %le %le %le", &n, &l, &v1, &v2, &k)) {
    if (n <= k) {
      time = l / v2;
      printf("%.10f", time);
    } else {
      double d;
      double N = 1.;
      int flag = 1;
      while (flag == 1) {
        if (N * k >= n)
          flag = 0;
        else
          N++;
      }
      d = l / (N - (v2 - v1) * (N - 1) / (v1 + v2));
      time = d / v2 + (l - d) / v1;
      printf("%.10f", time);
    }
  }
}
