Вычисление корней уравнения и построение графика

Dim a As Double
Dim b As Double
Dim x As Double
Dim eps As Double
Dim s As Integer
Dim bytI As Integer
Dim sngX As Single
 
Public Function func(x As Double) As Double
    func = (s * x) - ((Cos(pi * x)) ^ 2)
End Function
 
Private Sub Graf()
    picGraf.Cls
    picGraf.Scale (-3, 2)-(3, -2)
    For sngX = -3 To 3 Step 0.001
        picGraf.PSet (sngX, func(x))
    Next sngX
       
'X
    picGraf.Line (-3, 0)-(3, 0)
    For bytI = -3 To 3
        picGraf.PSet (bytI, 0)
        picGraf.Print bytI
    Next bytI
    
'Y
    picGraf.Line (0, 2)-(0, -2)
    For bytI = -2 To 2
        picGraf.PSet (0, bytI)
        picGraf.Print bytI
    Next bytI
  
End Sub
 
 
 
Private Sub cmdStart_Click()
 lblResults.Caption = Format(Reshenie(a, b), "0.000000")
 Graf
End Sub
'Forma End ===================================================
 
 
Private Function Reshenie(a As Double, b As Double) As Double
    a = -1 
    b = 0.7  
    s = Int(txtS.Text)
    eps = 0.000001
  
    While (Abs(b - a) > eps)
 
        a = b - (b - a) * func(b) / (func(b) - func(a)) 
        b = a - (a - b) * func(a) / (func(a) - func(b)) 
    Wend
        Reshenie = b     
End Function