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);
}