using System;

​

public class MyProgram

{

    public static void Main(string[] args)

    {

        string ans;

​

        Console.WriteLine("Does the equation contains a Trigonometrical fucntion, Exponential and/or Logarithmic function?");

        Console.WriteLine("Y / N");

        ans = Console.ReadLine();

        if (ans == "Y" || ans == "Yes" || ans == "YES" || ans == "yes" || ans == "y")

        {

            Console.WriteLine("You will learn this in a later chapter");

        }

        else

        {

            Console.WriteLine("Is f(x) = u/v? Division of two separate x terms");

            Console.WriteLine("Y / N");

            ans = Console.ReadLine();

            if (ans == "Y" || ans == "Yes" || ans == "YES" || ans == "yes" || ans == "y")

            {

                Console.WriteLine("Quotient Rule f(x) = u/v, where u and v can be differentiated wrt x");

                Console.WriteLine("f ' (x) = [ v(du/dx) - u(dv/dx) / v² ]");

                Console.WriteLine("(Differentiate the top multiply the bottom) minus (Differentiate the bottom multiply the top). Divided by bottom square");

            }

            else

            {

                Console.WriteLine("Is it f(x) = uv? Multiplication of two separate x terms");

                Console.WriteLine("Y / N");

                ans = Console.ReadLine();

                if (ans == "Y" || ans == "Yes" || ans == "YES" || ans == "yes" || ans == "y")

                {

                    Console.WriteLine("Product Rule, f(x) = uv where u and v can be differentiated wrt x");

                    Console.WriteLine("f ' (x) = v(du/dx) + u(dv/dx)");

                    Console.WriteLine("(Differentiate the 1st term multiply 2nd term) + (Differentiate 2nd term multiply first term)");

                }

                else

                {

                    Console.WriteLine("Is it f(x) = k(u)ⁿ? Where u is a bracket with x term and k is a constant");

                    Console.WriteLine("Y / N");

                    ans = Console.ReadLine();

                    if (ans == "Y" || ans == "Yes" || ans == "YES" || ans == "yes" || ans == "y")

                    {

                        Console.WriteLine("Chain rule. f(x) = k(u)ⁿ, where u is a bracket with x term in it");

                        Console.WriteLine("f ' (x) = knuⁿ⁻¹ * du/dx");

                        Console.WriteLine("Bring down the power, power minus 1, differentiate the bracket");

                    }

                    else

                    {

                        Console.WriteLine("Is f(x) = kxⁿ? A polynomial and k is a constant");

                        Console.WriteLine("Y / N");

                        ans = Console.ReadLine();

                        if (ans == "Y" || ans == "Yes" || ans == "YES" || ans == "yes" || ans == "y")

                        {

                            Console.WriteLine("Power Rule f(x) = kxⁿ, k is a constant");

                            Console.WriteLine("f ' (x) = nkxⁿ⁻¹");

                            Console.WriteLine("bring down the power, power minus 1");

                        }

                        else

                        {

                            Console.WriteLine("Check again from the start");

                        }

                    }

                }

            }

        }

    }

    // .NET can only read single characters or entire lines from the

    // console. The following function safely reads a double value.

    private static double inputValue()

    {

        double result;

        while (!double.TryParse(Console.ReadLine(), out result));

        return result;

    }

}

​