#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int main() {
  long long int n, l, v1, v2, k;
  cin >> n >> l >> v1 >> v2 >> k;
  double tp2 = (double)l / (double)v1;
  double tp1 = (double)l / (double)v2;
  if (v1 >= v2) {
    printf("%.10lf\n", tp2);
    return 0;
  }
  long long int tr = (n - 1) / k;
  tr++;
  if (tr == 1) {
    printf("%.10lf\n", tp1);
    return 0;
  }
  long long int num = l * (v2 + v1);
  long long int den = 2 * tr * v1 + v2 - v1;
  double ax = (double)num / (double)den;
  double bx = (double)l - ax;
  double ans = ax / (double)v2 + bx / (double)v1;
  ans = min(ans, tp2);
  printf("%.10lf\n", ans);
  return 0;
}
