using System;

public class Program

{

    public static void Main()

    {

        // Arithmetic Functions inside C#

        double tau = 2 * 3.14159;

        double sqrt = Math.Sqrt(tau);

        double pow = Math.Pow(tau,3);

        double abs = Math.Abs(tau);

        double rnd = Math.Round(tau);

        double cosine = Math.Cos(tau);

        // math class also contain field or constaints certain value to read. 

        double pi = Math.PI; // field increased precision!!!!

        Console.WriteLine(pi); 

        Console.WriteLine(abs);

        Console.WriteLine(sqrt);

        Console.WriteLine(rnd);

        Console.WriteLine(cosine);

    }

}