Многочлен integral

#include <iostream>
#include <vector>
#include <cmath>
#include <limits.h>

using namespace std;

double integral(int x, int k) {
    return pow(x, k) / k;
}

int main() {

	int n;
	cin >> n;
	n++;
	double *arr = new double[n];
	for(int i = 0; i < n; i++) {
	    cin >> arr[i];
	}

	int a, b;
	cin >> a >> b;

	int c;
	cin >> c;

	double res = 0;
	for(int i = n - 1; i >= 0; i--) {
	    arr[i] = arr[i] * (integral(b, i + 1) - integral(a, i + 1));
	    res += arr[i];
	}

    cout << c * res;

	return 0;
}