public static string lagrang(double[] x, int node, double[] y)
        {
            Polynomial temp    = new Polynomial();
            Polynomial onepoly = new Polynomial();


            bool loop = false;

            for (int i = 0; i < node; i++)
            {
                for (int j = 0; j < node; j++)
                {
                    loop = false;
                    if (i != j)
                    {
                        loop = true;
                        temp = new Polynomial();
                        double amthallagrang = x[i] - x[j];
                        temp = Polynomial.insert(y[i] * amthallagrang, 1, temp);
                        temp = Polynomial.insert(y[i] * amthallagrang * -x[j], 0, temp);
                    }
                    if (loop)
                    {
                        onepoly = Polynomial.add(temp, onepoly);
                    }
                }
            }
            return(Polynomial.tostring(onepoly));
        }
        private void Calculate_Click(object sender, EventArgs e)
        {
            string Method = comboBox1.Text;

            string[] allMethod   = { "newton" };
            string   AnyOfMethod = Array.Find(allMethod, s => s.Equals(Method));

            if ((Method != AnyOfMethod))
            {
                MessageBox.Show("This Is Not Method", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            else
            {
                bool XarrayZero = false;
                bool YarrayZero = false;
                xcolum     = CreatXarray(ref ThereIsErrorX);
                ycolum     = CreatYarray(ref ThereIsErrorY);
                XarrayZero = Share.IfallZero(xcolum);
                YarrayZero = Share.IfallZero(ycolum);
                if ((ThereIsErrorX != true) && (ThereIsErrorY != true) && (XarrayZero != true) && (YarrayZero != true))
                {
                    switch (Method)
                    {
                    case "newton":
                    {
                        textBox2.Visible = true;
                        textBox3.Visible = true;
                        Polynomial newton = new Polynomial();
                        newton        = deriveationclass.Newton(ycolum, xcolum[1] - xcolum[0], NumOfNode, xcolum[0]);
                        textBox2.Text = Polynomial.tostring(newton);
                        newton        = deriveationclass.Newtonsecond(ycolum, xcolum[1] - xcolum[0], NumOfNode,
                                                                      xcolum[0]);
                        textBox3.Text = Polynomial.tostring(newton);
                    }
                    break;
                    }
                }
            }
        }
        private void Send_Click(object sender, EventArgs e)
        {
            bool   XarrayZero = false;
            bool   YarrayZero = false;
            string Method     = comboBox1.Text;

            string[] allMethod = { "General Methode", "Spline", "Lagrange", "Newton", "Least Square Method" };
            if (Method != ".......")
            {
                xcolum     = CreatXarray(ref ThereIsErrorX);
                XarrayZero = Share.IfallZero(xcolum);
                if (XarrayZero != true)
                {
                    ycolum = CreatYarray(ref ThereIsErrorY);
                }
                YarrayZero = Share.IfallZero(ycolum);
                string AnyOfMethod = Array.Find(allMethod, s => s.Equals(Method));
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    if ((Method == AnyOfMethod))
                    {
                        comboBox1.Enabled = false;
                    }
                    else
                    {
                        MessageBox.Show("This Is Not Method", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                }
            }
            XarrayZero = Share.IfallZero(xcolum);
            YarrayZero = Share.IfallZero(ycolum);
            switch (Method)
            {
            case "General Methode":
            {
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    #region General Methode

                    double[,] matrx;
                    matrx = new double[NumOfNode, NumOfNode];
                    matrx = InterpolationClass.CreatVandrmondmatrix(NumOfNode, xcolum);
                    double determatrx = InterpolationClass.determine(matrx);
                    double[,] another = new double[NumOfNode, NumOfNode];
                    Polynomial temp = new Polynomial();
                    double[]   Constant;
                    Constant = new double[NumOfNode];
                    for (int j = 0; j < NumOfNode; j++)
                    {
                        another = InterpolationClass.creatanothermatrix(j, xcolum, ycolum, NumOfNode);
                        double deternother = InterpolationClass.determine(another);
                        Constant[j] = deternother / determatrx;
                    }
                    for (int i = 0; i < Constant.Length; i++)
                    {
                        temp = Polynomial.insert(Constant[i], i, temp);
                    }
                    string result = Polynomial.tostring(temp);


                    if (MessageBox.Show("If You Have An Internet Connection Click Yes To Show The Function On Net Or Click No To See It Here", "Internet Connection",
                                        MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
                        DialogResult.Yes)
                    {
                        string url = "http://texify.com/?" + result;
                        Process.Start(url);
                    }
                    else
                    {
                        label3.Visible       = true;
                        richTextBox1.Visible = true;
                        richTextBox1.Text    = result;
                    }

                    Send.Enabled    = false;
                    Refresh.Visible = true;

                    #endregion
                }
            }
            break;

            case "Least Square Method":
            {
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    #region Least Square Method
                    int      exp = NumOfNode - 1;
                    double   sum;
                    double[] tableX = new double[2 * exp];
                    double[] tableY = new double[NumOfNode];
                    for (int j = 0; j < (2 * exp); j++)
                    {
                        sum = 0;
                        for (int i = 0; i < NumOfNode; i++)
                        {
                            sum       = sum + Math.Pow(xcolum[i], j + 1);
                            tableX[j] = sum;
                        }
                    }
                    for (int j = 0; j < NumOfNode; j++)
                    {
                        sum = 0;
                        for (int i = 0; i < NumOfNode; i++)
                        {
                            if (j == 0)
                            {
                                sum = sum + ycolum[i];
                            }
                            else
                            {
                                sum = sum + (Math.Pow(xcolum[i], j) * ycolum[i]);
                            }
                            tableY[j] = sum;
                        }
                    }
                    double[,] squer = new double[NumOfNode, NumOfNode];
                    squer[0, 0]     = NumOfNode;
                    for (int i = 1; i < NumOfNode; i++)
                    {
                        squer[0, i] = tableX[i - 1];
                    }
                    for (int i = 1; i < NumOfNode; i++)
                    {
                        for (int j = 0; j < NumOfNode; j++)
                        {
                            squer[i, j] = tableX[i + j - 1];
                        }
                    }
                    double[] A = new double[NumOfNode];
                    double   d = InterpolationClass.determine((double[, ])squer.Clone());
                    for (int j = 0; j < NumOfNode; j++)
                    {
                        A[j] = InterpolationClass.ChangeXY((double[, ])squer.Clone(), tableY, j, NumOfNode) / d;
                    }
                    Send.Enabled    = false;
                    Refresh.Visible = true;

                    #endregion
                }
            }
            break;

            case "Lagrange":
            {
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    #region Lagrange

                    {
                        string result = InterpolationClass.lagrang(xcolum, NumOfNode, ycolum);
                        if (MessageBox.Show("If You Have An Internet Connection Click Yes To Show The Function On Net Or Click No To See It Here", "Internet Connection",
                                            MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
                            DialogResult.Yes)
                        {
                            string url = "http://texify.com/?" + result;
                            Process.Start(url);
                        }
                        else
                        {
                            label3.Visible       = true;
                            richTextBox1.Visible = true;
                            richTextBox1.Text    = result;
                        }
                    }

                    #endregion
                }
            }
            break;

            case "Spline":
            {
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    #region Splin
                    {
                        double point = 0;
                        if ((textBox2.Text != null) && (Share.Isnumber(textBox2.Text)))
                        {
                            point = double.Parse(textBox2.Text);
                            string result = Polynomial.tostring(InterpolationClass.Splin(xcolum, ycolum, NumOfNode, point));
                            if (MessageBox.Show("If You Have An Internet Connection Click Yes To Show The Function On Net Or Click No To See It Here", "Internet Connection",
                                                MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
                                DialogResult.Yes)
                            {
                                string url = "http://texify.com/?" + result;
                                Process.Start(url);
                            }
                            else
                            {
                                label3.Visible       = true;
                                richTextBox1.Visible = true;
                                richTextBox1.Text    = result;
                            }
                        }
                        else
                        {
                            MessageBox.Show("Error Entry", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                        }
                    }
                    #endregion
                }
            }
            break;

            case "Newton":
            {
                if ((XarrayZero != true) && (YarrayZero != true) && (ThereIsErrorX != true) && (ThereIsErrorY != true))
                {
                    #region Newton
                    double[,] Temp = InterpolationClass.newtonftab(xcolum, ycolum, NumOfNode);
                    Polynomial Newton = InterpolationClass.newtonemethod(xcolum, ycolum, Temp, NumOfNode);
                    string     result = Polynomial.tostring(Newton);
                    if (MessageBox.Show("If You Have An Internet Connection Click Yes To Show The Function On Net Or Click No To See It Here", "Internet Connection",
                                        MessageBoxButtons.YesNo, MessageBoxIcon.Question) ==
                        DialogResult.Yes)
                    {
                        string url = "http://texify.com/?" + result;
                        Process.Start(url);
                    }
                    else
                    {
                        label3.Visible       = true;
                        richTextBox1.Visible = true;
                        richTextBox1.Text    = result;
                    }

                    #endregion
                }
            }
            break;

            default:
            {
                if (Method == ".......")
                {
                    MessageBox.Show("No Method Is Selceted ", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            break;
            }
        }