Вычислить выражение и найти минимальное значение функции - Visual Basic .NET

Формулировка задачи:

                    Листинг программы
                
 
                            
                        
Public Class Form1
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim Z As Single
        Dim Xmin As Single
        Dim Xmax As Single
        Dim DX As Single
        Dim Ymin As Single
        Dim Ymax As Single
        Dim Dy As Single
        Dim Sy As Single
        Dim Ny As Single
        Dim Zmin As Single
 
        Xmin = 0
        Xmax = 1
        DX = 0.1
 
        Ymin = 0
        Ymax = 1
        Dy = 0.1
 
        Sy = 0
        Ny = 0
 
        RichTextBox1.Text = RichTextBox1.Text + "Y \ X" + Chr(9)
        For X = Xmin To Xmax Step DX
            RichTextBox1.Text = RichTextBox1.Text + Str(Format(X, "00.000")) + Chr(9)
        Next
        RichTextBox1.Text = RichTextBox1.Text + Chr(10)
        For Y = Ymin To Ymax Step Dy
            RichTextBox1.Text = RichTextBox1.Text + Str(Format(Y, "00.000")) + Chr(9)
            For X = Xmin To Xmax Step DX
 
                Z = (Math.Sqrt(Math.Abs(X ^ 3 - (Math.Sqrt(Y)) + (X + 2 * Y) ^ 2)))
                RichTextBox1.Text = RichTextBox1.Text + Str(Format(Z, "00.000")) + Chr(9)
 
            Next
            RichTextBox1.Text = RichTextBox1.Text + Chr(10)
        Next
        RichTextBox1.Text = RichTextBox1.Text + "Zmin=" + Str(Z) + Chr(10)
    End Sub
End Class

Вот как бы программа, а как найти минимальное значение функции?

Решение задачи: «Вычислить выражение и найти минимальное значение функции»

textual
                            Листинг программы 
                        
 
                            
                        
Public Class Form1
 
  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim Z As Single
    Dim Xmin As Single
    Dim Xmax As Single
    Dim DX As Single
    Dim Ymin As Single
    Dim Ymax As Single
    Dim Dy As Single
    Dim Sy As Single
    Dim Ny As Single
    Dim Zmin As Single = Single.MaxValue
 
 
    Xmin = 0
    Xmax = 1
    DX = 0.1
 
    Ymin = 0.1
    Ymax = 1
    Dy = 0.1
 
    Sy = 0
    Ny = 0
 
 
    RichTextBox1.Text = RichTextBox1.Text + "Y \ X" + Chr(9)
    For X = Xmin To Xmax Step DX
      RichTextBox1.Text = RichTextBox1.Text + Str(Format(X, "00.000")) + Chr(9)
    Next
    RichTextBox1.Text = RichTextBox1.Text + Chr(10)
    For Y = Ymin To Ymax Step Dy
      RichTextBox1.Text = RichTextBox1.Text + Str(Format(Y, "00.000")) + Chr(9)
      For X = Xmin To Xmax Step DX
 
        Z = (Math.Sqrt(Math.Abs(X ^ 3 - (Math.Log(Math.Abs(Y))) + (X + 2 * Y) ^ 2)))
        RichTextBox1.Text = RichTextBox1.Text + Str(Format(Z, "00.000")) + Chr(9)
 
        If Zmin > Z Then Zmin = Z
 
      Next
      RichTextBox1.Text = RichTextBox1.Text + Chr(10)
    Next
    RichTextBox1.Text = RichTextBox1.Text + "Zmin=" + Str(Zmin) + Chr(10)
  End Sub
 
End Class