#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization("unroll-loops")
using namespace std;
long long max3(long long x, long long y, long long z) {
  return max(max(x, y), z);
}
long long min3(long long x, long long y, long long z) {
  return min(min(x, y), z);
}
const long long N = 1e5 + 10, M = 2e5 + 10, M2 = 1e6 + 10, mod = 1e9 + 7,
                inf = 1e17 + 10;
const long long INF = 1e9 + 7;
void add(long long& a, long long b) {
  a += b;
  if (a >= mod) {
    a -= mod;
  }
}
long long X[] = {0, 1, 0, -1};
long long Y[] = {-1, 0, 1, 0};
long long power(long long x, long long n) {
  long long result = 1;
  while (n > 0) {
    if (n % 2 == 1) result = (result * x) % mod;
    x = ((x % mod) * (x % mod)) % mod;
    n = n / 2;
  }
  return result;
}
long long n, l, v1, v2, k;
bool check(long double t) {
  long double newdist = l - v1 * t;
  if (newdist <= 0) return 1;
  long double bustime = newdist / (v2 - v1);
  long double cover = newdist / (v2 + v1);
  long double groups = (n + k - 1) / k;
  long double timetaken = groups * bustime + (groups - 1) * cover;
  return (timetaken <= t);
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> l >> v1 >> v2 >> k;
  long double ans = 1e18;
  long double hi = 1e18;
  long double lo = 0;
  for (long long i = 1; i <= 500; i++) {
    long double mid = (lo + hi) / 2;
    if (check(mid)) {
      hi = mid;
      ans = min(ans, mid);
    } else
      lo = mid;
  }
  cout << fixed << setprecision(15) << ans;
  return 0;
}
