using System;
using System.Collections;
namespace restless
{
class Program
{
static void Main(string[] args)
{
for (double i = 0.1; i < 2.6; i += 0.2)
{
double y = Math.Sqrt(i) - 2 * Math.Cos(0.5 * Math.PI * i);
Console.WriteLine($"X={i} || Y={y}");
}
Console.ReadKey();
}
}
}
