The program does not output a number. What is the problem?

Question

C++ / C#

The program must find the roots of the equation by Newton's method

class Program
    {
        static void Main(string[] args)

        {
            const float e = 0.0001f;
            float x, xLast, fx, _fx;
            Console.WriteLine("Введите начальное приближение к корню");
             x = Convert.ToSingle(Console.ReadLine());
            do
            {
                fx = 2 * Convert.ToSingle(Math.Log(x) - 1 / x);
                _fx = (2 / x) + (1 / x * x);
                xLast = (-2 / x * x) - (2 / x * x * x);
               Convert.ToDouble( x = xLast - fx / _fx);
            }
            while( Math.Abs(fx) > e);
            
            Console.WriteLine( "Значение корня уравнения ={0} ", x);
            Console.Read();
               }
    }
}

Answer 1

Because the derivative is calculated incorrectly and the method itself is implemented incorrectly.