// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002321/double-acos

​

// @nuget: Z.ExtensionMethods

​

using System;

public class Program

{

    public static void Main()

    {

        double[] doubles = { 0, 0.333, 0.667, 1 };

        foreach (double value in doubles)

        {

            // C# Extension Method: Double - Acos

            Console.WriteLine("Acos({0}) = {1}", value, value.Acos());

        }

    }

}