#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep(i, n) for (int i = 0; i < int(n); i++) using namespace std; long long MOD = 1000000007; long long INF = 1000000000000000; //10^15 typedef long long ll; typedef unsigned long long ull; ll powMod(ll x, ll n, ll mod) { if (n == 0) return 1; ll t = powMod(x, n/2, mod); t = t * t % mod; if (n & 1) return t * x % mod; return t; } int main(void) { int n; double a[1010]; cin >> n; rep(i, n) cin >> a[i]; double N = n; double aav = 0; rep(i, n) aav += a[i]; aav /= N; double y, x; rep(i, n) { y += (a[i] - aav) * ((double)i - (N + 1.0)/2.0); } y /= N * (N + 1.0) * (2.0 * N + 1.0)/6.0 - (N * (N + 1.0) * (N + 1.0))/4.0; x = aav - y * (N + 1.0) / 2.0; cout << x + y << " " << y << endl; double c = 0; rep(i, n) { double k = a[i] - x - y - (double)i * y; c += k * k; } cout << std::setprecision(15) << c << endl; }