辐射3自动步枪:跪请vb高手

小弟自己编了一个画方程组图象的软件,可是好象有很大的问题.就是图象是v字型,根本不是一次方程图象.望大虾指教!
代码如下:
Public k1, k2, b1, b2 As Double
Private Sub Command1_Click()
Picture1.Line (33.866, 0)-(33.866, 22.489 * 2)
Picture1.Line (0, 22.489)-(33.866 * 2, 22.489)
If Text1.Text = "" Or Text3.Text = "" Then
Command1.Enabled = False
Label6.Caption = "请输入方程!"
GoTo last
ElseIf Not Text1.Text = "" And Text3.Text = "" And Text2.Text <> "" And Text4.Text <> "" Then
k1 = Text1.Text
k2 = Text3.Text
Picture1.Line (33.866, 22.489)-(63.866 / Tan(k1), 63.866)
Picture1.Line (33.866, 22.489)-(3.866 / Tan(k1), 3.866)
Picture1.Line (33.866, 22.489)-(63.866 / Tan(k2), 63.866)
Picture1.Line (33.866, 22.489)-(3.866 / Tan(k2), 3.866)
Label6.Caption = "图画完了。"
Command1.Enabled = False
GoTo last
Else
k1 = Text1.Text
k2 = Text3.Text
b1 = Text2.Text
b2 = Text4.Text
Picture1.Line (33.866, 22.489 + b1)-(63.866 / Tan(k1), 63.866)
Picture1.Line (33.866, 22.489 + b1)-(3.866 / Tan(k1), 3.866)
Picture1.Line (33.866, 22.489 + b2)-(63.866 / Tan(k2), 63.866)
Picture1.Line (33.866, 22.489 + b2)-(3.866 / Tan(k2), 3.866)
Label6.Caption = "图画完了。"
Command1.Enabled = False
GoTo last
last: End If
End Sub

Private Sub Command2_Click()
Command1.Enabled = True
Text1.Text = ""
Text2.Text = ""
Text3.Text = ""
Text4.Text = ""
Label6.Caption = ""
Picture1.Cls
Picture1.Line (33.866, 0)-(33.866, 22.489 * 2)
Picture1.Line (0, 22.489)-(33.866 * 2, 22.489)
End Sub

Private Sub Form_Load()
Left = (Screen.Width - Width) / 2
Top = (Screen.Height - Height) / 2
End Sub
Private Sub Text1_gotfocus()
Text1.BackColor = &HFFC0C0
End Sub
Private Sub text1_lostfocus()
Text1.BackColor = &HFFFFFF
End Sub
Private Sub Text2_gotfocus()
Text2.BackColor = &HFFC0C0
End Sub
Private Sub text2_lostfocus()
Text2.BackColor = &HFFFFFF
End Sub
Private Sub Text3_gotfocus()
Text3.BackColor = &HFFC0C0
End Sub
Private Sub text3_lostfocus()
Text3.BackColor = &HFFFFFF
End Sub
Private Sub Text4_gotfocus()
Text4.BackColor = &HFFC0C0
End Sub
Private Sub text4_lostfocus()
Text4.BackColor = &HFFFFFF
End Sub
Private Sub text1_KeyPress(KeyAscii As Integer)
Select Case KeyAscii
Case Asc("0") To Asc("9"), vbKeyBack
Case Asc("-"), vbKeyBack
Case Asc("."), vbKeyBack
Case Else
KeyAscii = 0
End Select
End Sub
Private Sub text2_KeyPress(KeyAscii As Integer)
Select Case KeyAscii
Case Asc("0") To Asc("9"), vbKeyBack
Case Asc("-"), vbKeyBack
Case Asc("."), vbKeyBack
Case Else
KeyAscii = 0
End Select
End Sub
Private Sub text3_KeyPress(KeyAscii As Integer)
Select Case KeyAscii
Case Asc("0") To Asc("9"), vbKeyBack
Case Asc("-"), vbKeyBack
Case Asc("."), vbKeyBack
Case Else
KeyAscii = 0
End Select
End Sub
Private Sub text4_KeyPress(KeyAscii As Integer)
Select Case KeyAscii
Case Asc("0") To Asc("9"), vbKeyBack
Case Asc("-"), vbKeyBack
Case Asc("."), vbKeyBack
Case Else
KeyAscii = 0
End Select
End Sub