Отделение корней уравнения методом половинного деления

Private Sub cmdDetect_Click()
PicDetect.Cls
Dim a As Integer, b As Integer, h As Integer
a = Val(txtMinX.Text)
b = Val(txtMaxX.Text)
h = Val(stepX.Text)
Dim x1 As Integer, x2 As Integer, y1 As Integer, y2 As Integer
Dim k As Integer
k = 0
x1 = a
x2 = a + h
y1 = y(x1)
Do
y2 = y(x2)
If y1 * y2 < 0 Then
k = k + 1
Pic.Detect.Print k; "-é êîðåíü ["; x1; ";"; x2; "]"
End If
x1 = x2
x2 = x1 + h
y1 = y2
loopwhile x2 <= b
If k = 0 Then Pic.Detect.Print "Êîðíåé íåò"
End Sub
 
Private Sub cmdStart_Click()
Dim minX As Integer, maxX As Integer, minY As Integer, maxY As Integer
minX = Val(txtMinX.Text)
maxX = Val(txtMaxX.Text)
minY = Val(txtMinY.Text)
maxY = Val(txtMaxY.Text)
Pic.Scale (minX, maxY)-(maxX, minY)
Pic.Cls
Dim stepX As Single, stepY As Single
stepX = Val(txtStepX.Text)
stepY = Val(txtStepY.Text)
For x = minX To maxX Step stepX
Pic.Line (x, minY)-(x, maxY), vbGreen
Pic.PSet (x, 0), vbBlack
Pic.Print x
Next x
For t = minY To maxY Step stepY
Pic.Line (minX, y)-(maxX, y), vbGreen
Pic.PSet (0, y), vbBlack
Pic.Print y
Next
Pic.Line (minX, 0)-(maxX, 0), vbBlack
Pic.Line (0, minY)-(0, maxY), vbBlack
Pic.DrawWidth = 2
For x = minX To maxX Step stepX / 1000
y = (1 / 5) * x ^ 5 + 0.3 * x ^ 4 - (5 / 3) * x ^ 3 - x ^ 2 + 4 * x - 1.7
Pic.PSet (x, y), vbBlue
Next x
Pic.DrawWidth = 1
End Sub

Function SearchInt(a As Double, b As Double, h As Double) As Double()
 
Dim R() As Double
 
    ReDim R(1 To 10) As Double
 
    k% = 0
 
    f1# = (1 / 5) * a ^ 5 + 0.3 * a ^ 4 - (5 / 3) * a ^ 3 - a ^ 2 + 4 * a - 1.7
 
    For X# = a + h To b Step h
        
        f2# = (1 / 5) * X# ^ 5 + 0.3 * X# ^ 4 - (5 / 3) * X# ^ 3 - X# ^ 2 + 4 * X# - 1.7
        
        If Sgn(f1#) * Sgn(f2#) < 0 Then
           k% = k% + 1
           R(k%) = X# - h
           k% = k% + 1
           R(k%) = X#
        End If
           
        f1# = f2#
        
     Next X#
 
     If k% < 10 Then ReDim Preserve R(1 To k%) As Double
     
     SearchInt = R
 
End Function
 
Function BinSearch(a As Double, b As Double, eps As Double) As Double
 
    fa# = (1 / 5) * a ^ 5 + 0.3 * a ^ 4 - (5 / 3) * a ^ 3 - a ^ 2 + 4 * a - 1.7
    fb# = (1 / 5) * b ^ 5 + 0.3 * b ^ 4 - (5 / 3) * b ^ 3 - b ^ 2 + 4 * b - 1.7
 
    Do
    
      c# = 0.5 * (a + b)
    
      If Abs(b - a) <= eps Then
         BinSearch = c#
         Exit Function
      End If
    
      fc# = (1 / 5) * c# ^ 5 + 0.3 * c# ^ 4 - (5 / 3) * c# ^ 3 - c# ^ 2 + 4 * c# - 1.7
    
      If Sgn(fa#) * Sgn(fc#) < 0 Then
         b = c#
         fb# = fc#
      Else
         a = c#
         fa# = fc#
      End If
    
    Loop
 
End Function
 
Sub Test_2()
 
Dim Z() As Double
 
    Z = SearchInt(-3, 3, 0.1)
    
    n% = UBound(Z, 1) \ 2
    
    For ir% = 1 To n%
        p% = (ir% - 1) * 2 + 1
        a# = Z(p%)
        b# = Z(p% + 1)
        Debug.Print "Интервал корня: ["; a#; ","; b#; "] корень=";
        R# = BinSearch(a#, b#, 0.000001)
        Debug.Print R#
    Next ir%
        
End Sub

Function f#(x)
f = (1 / 5) * x ^ 5 + 0.3 * x ^ 4 - (5 / 3) * x ^ 3 - x ^ 2 + 4 * x - 1.7
End Function
 
Sub k(x, b, h, eps)
    Do
    a = x:         f1 = f(x)
    x = x + h:     f2 = f(x)
        If f1 * f2 < 0 Then
           b1 = x
                Do
                   c = (b1 + a) / 2
                   If f(a) * f(c) > 0 Then a = c Else b1 = c
                Loop While Abs(a - b1) > eps
i = i + 1: Print "x"; i; "="; c
        End If
     Loop While x <= b
End Sub
 
Private Sub Command1_Click()
k -100, 100, 0.1, 0.0001
End Sub