упростить программу

Option Explicit
Dim x0 As Double, y0 As Double
Dim b, c
Const x1 = 1, x2 = 2, hx = 0.25
Const y1 = 4.2, y2 = 5.1, hy = 0.3
Dim stroka As String, f As Boolean
 
Function a(x As Double, y As Double) As Double
On Error GoTo er
'Resume Next
a = Round((b ^ x + c ^ y) * Sin(x * y), 2)
Exit Function
er: MsgBox Err.Description
Text_b.Text = 10: Text_c.Text = 20
f = True
End Function
 
Private Sub Command1_Click()
f = False
b = Val(Text_b.Text): c = Val(Text_c.Text)
 
Text1.Text = "x\y" & Space(40 - Len("x\y"))
y0 = y1: stroka = ""
Do While y0 <= y2
stroka = stroka & y0 & Space(40 - Len(CStr(y0)))
y0 = y0 + hy
Loop
 
Text1.Text = Text1.Text & stroka & vbCrLf
 
x0 = x1
Do While x0 < x2
   stroka = ""
   y0 = y1
     Do While y0 <= y2
     If f Then Exit Sub
        stroka = stroka & a(x0, y0) & Space(30 - Len(CStr(y0)))
        y0 = y0 + hy
     Loop
  x0 = x0 + hx
 
stroka = x0 & Space(30 - Len(CStr(x0))) & stroka
Text1.Text = Text1.Text & stroka & vbCrLf
Loop
End Sub

Private Sub Command1_Click()
Dim l As Integer, V As Double, V_max As Double
 
Dim a As Integer, b As Integer, h As Integer
  a = 40: b = 80: h = 4
 
 
       List1.Clear
V_max = Vx(a)
List1.AddItem "l = " & a & " cm   " & "  V = " & Round(V_max, 2) & "  km/hod"
For l = a + h To b Step h
V = Vx(l)
List1.AddItem "l = " & l & " cm   " & "  V = " & Round(V, 2) & "  km/hod"
If V > V_max Then V_max = V
Next l
List1.AddItem "V_max=" & Round(V_max, 2) & "  km/hod"
End Sub
Function Vx(l As Integer) As Double
Dim pi
  pi = 4 * Atn(1)
Const g = 3600 ^ 2 * 9.81  'm/c^2=3600^2*9.81 m/hod^2
Const L_ = 12.5 / 1000 'm =12.5/1000 km
'l cm = l/100 m
'Vx km/hod
Vx = (L_ / (2 * pi)) * Sqr(g / (l / 100))
 
End Function