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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static double f(double x)
        {
            return Math.Asin(Math.Sqrt(1 / (1 + x)));
        }
        static double F(double x)
        {
            return x * Math.Asin(Math.Sqrt(x / (1 + x))) - Math.Sqrt(x) + Math.Atan(Math.Sqrt(x));
        }
        static double Simpson(double a, double b, int n)
        {
            double s, x, h;
            s = f(a) + f(b);
            h = (b - a) / n;
            x = a + h;
            do
            {
                x = x + h;
                s = s + 2 * F(x);
            }
            while (x < b);
            return h / 3 * (s + F(3) - F(0));

        }
        static void Main(string[] args)
        {
            double Int;
            Int = Simpson(0, 3, 36);
            Console.WriteLine("Интеграл = {0:f4}", Int);
            Console.ReadKey();
        }
    }
}