lichniy_silniy_cisharp/testing/FunctionsMath.cs

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


namespace testing
{
    internal class FunctionsMath
    {

        public double pow(double a, double pow)
        {
            for (int i = 1; i < pow; i++) 
            {
                a *= a;   
            }
            return a;
        }


        public struct Trigonometry 
        {
            public static double tg(double a) => Math.Sin(a) / cos(a);

            public static double cos(double a)
            {
                if (Math.Sin(a) > 0)
                    return Math.Sqrt(1 - (Math.Sin(a) * Math.Sin(a)));
                else
                    return -Math.Sqrt(1 - (Math.Sin(a) * Math.Sin(a)));
            }

            public static double sec(double a) => 1 / cos(a);

            public static double cot(double a) => cos(a) / Math.Sin(a);
        }


       public  struct Logarifms
        {

            public static double log(double a, double b)
            {
                double res = 0;
                if (a > 0 && a != 1 && b > 0)
                {
                    res = Math.Log(b) / Math.Log(a);
                }
                return res;
            }
        }

       
    }
}