Untitled

#include <iostream>
#include <cmath>

double s1(int n, double x) {
    double result = 0;
    for (int i = 1; i <= n; ++i) {
        result += (pow(x, i)) / (i * (i + 1));
    }
    return result;
}

int factorial(int n) {
    if (n == 0 || n == 1) {
        return 1;
    } else {
        return n * factorial(n - 1);
    }
}

double s2(int n) {
    double result = 0;
    for (int i = 0; i <= n; ++i) {
        result += 1.0 / factorial(i);
    }
    return result;
}

double s3(int n, double x) {
    double result = 0;
    for (int i = 0; i <= n; ++i) {
        result += pow(x, 2 * i + 1);
    }
    return result;
}

double s4(int n, double x) {
    return s1(n, x) * 1 + s2(n) * 2 + s3(n, x) * 3;
}

int main() {
    int n;
    double x;
    std::cout << "Nhap gia tri cua n: ";
    std::cin >> n;
    std::cout << "Nhap gia tri cua x: ";
    std::cin >> x;

    double result1 = s1(n, x);
    std::cout << "Ket qua: " << result1 << std::endl;
    double result2 = s2(n);
    std::cout << "Ket qua: " << result2 << std::endl;
    double result3 = s3(n, x);
    std::cout << "Ket qua: " << result3 << std::endl;
    double result4 = s4(n, x);
    std::cout << "Ket qua: " << result4 << std::endl;

    return 0;
}