HomeTask

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FileDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lines = File.ReadAllLines("NUMBERS.TXT");
            foreach (var item in lines)
            {
                try
                {
                    double num = double.Parse(item);
                    Console.WriteLine(calc(num));
                }
                catch (Exception)
                {
                    Console.WriteLine("Error in line: {0}",item);
                }
            }
        }
        public static double calc(double x)
        {
            double s = 0;
            for (int i = 1; i <= 50; i++)
                s += x / (i * i * i);
            return s;
        }

    }
}