public class Simpson {

    double Res = 0, Resc = 0, Resn = 0;

    public Simpson(double a, double b, float n){
        double h = (b - a) / n;
        Resc = f(a + h);
        for (int i = 2; i < n; i += 2)
        {
            Resc += f(a + (i + 1) * h);
            Resn += f(a + i * h);
        }
        Res = f(a) + 4 * Resc + 2 * Resn  + f(b);
        Res = Res*h / 3;

        System.out.println("Значение интеграла " + Res);
    }

    public static double f(double xn) {
        return xn * Math.sin(xn);
    }

    public static void main (String[]args){
        Simpson L1 = new Simpson(0, 1.6, 6);
        Simpson L2 = new Simpson(0, 1.6, 12);
        Simpson L3 = new Simpson(0, 1.6, 60);
        Simpson L4 = new Simpson(0, 1.6, 600);
    }
}