怎么在VB中绘制数学函数图象?

　　第一步,新建一个工程,新建一个Form1,在上面添加一个picture控件和一个command控件,然后选中此控件,右击"复制",在窗体空白处右击"粘贴",在弹出的对话框中选择"是",创建了一个Command控件数组,复制,使窗体上总共出现7个Command控件,然后复制代码:
　　Const Pi = 3.1415926535 '定义圆周率
　　Dim a, wor
　　Dim i As Integer
　　Static Function Loge(X)
　　Loge = Log(X) / Log(Exp(1))
　　End Function
　　'定义用于在Picture1上的一个位置打印字符函数
　　Private Function PrintWord(X, y, Word As String)
　　With Picture1
　　.CurrentX = X
　　.CurrentY = y
　　.ForeColor = RGB(0, 0, 255)
　　End With
　　Picture1.Print Word
　　End Function
　　Private Function DrawDot(Px, Py, Color)
　　Picture1.PSet (Px, Py), Color
　　End Function
　　Sub XY() '建立直角坐标系
　　Picture1.DrawWidth = 1 '设置线条宽度
　　Picture1.Cls
　　'设定用户坐标系，坐标原点在Picture1中心
　　Picture1.Scale (-10, 10)-(10, -10)
　　Picture1.Line (-10, 0)-(10, 0), RGB(0, 0, 255)
　　Picture1.Line -(9.5, 0.5), RGB(0, 0, 255)
　　Picture1.Line (10, 0)-(9.5, -0.5), RGB(0, 0, 255)
　　Picture1.ForeColor = RGB(0, 0, 255)
　　Picture1.Print "X"
　　'画 X 轴
　　Picture1.Line (0, -10)-(0, 10), RGB(0, 0, 255)
　　Picture1.Line -(0.5, 9.5), RGB(0, 0, 255)
　　Picture1.Line (0, 10)-(-0.5, 9.5), RGB(0, 0, 255)
　　Picture1.Print "Y"
　　'画 Y 轴
　　For lin = -9 To 9
　　Picture1.Line (lin, 0)-(lin, 0.25)
　　wor = PrintWord(lin - 0.5, -0.5, Str(lin))
　　Picture1.Line (0, lin)-(-0.25, lin)
　　If lin <> 0 Then
　　wor = PrintWord(-0.9, lin, Str(lin))
　　End If
　　Next lin
　　Picture1.DrawWidth = 2
　　End Sub
　　Private Sub Command1_Click(Index As Integer)
　　Select Case Index
　　Case 0
　　For a = -3 To 3 Step Pi / 6000
　　Dot = DrawDot(a, a ^ 2, RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(4, 9, "二次曲线 y=x^2")
　　Case 1
　　For a = -9 To 9 Step Pi / 6000
　　Dot = DrawDot(a, a, RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(8, 5, "一次曲线 y=x")
　　Case 2
　　For a = -9 To 3 Step Pi / 6000
　　Dot = DrawDot(a, Exp(a), RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(4, 9, "指数曲线 y=e^x")
　　Case 3
　　For a = 0.0001 To 9 Step Pi / 6000
　　Dot = DrawDot(a, Loge(a), RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(8, 3, "对数曲线 y=ln x")
　　Case 4
　　For a = -10 To 10 Step Pi / 6000
　　Dot = DrawDot(a, Sin(a), RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(-5, 2, "正弦曲线 y=sin x")
　　Case 5
　　For a = -10 To 10 Step Pi / 6000
　　Dot = DrawDot(a, Cos(a), RGB(0, 0, 0))
　　Next a
　　wor = PrintWord(-9, 2, "余弦曲线 y=cos x")
　　Case 6
　　XY
　　End Select
　　End Sub
　　Private Sub Form_Load()
　　Me.Caption = "数学函数作图?quot;"
　　Me.Show
　　Me.AutoRedraw = True
　　Picture1.AutoRedraw = True
　　Command1(0).Caption = "二次曲线"
　　Command1(1).Caption = "一次曲线"
　　Command1(2).Caption = "指数曲线"
　　Command1(3).Caption = "对数曲线"
　　Command1(4).Caption = "正弦曲线"
　　Command1(5).Caption = "余弦曲线"
　　Command1(6).Caption = "清空"
　　XY
　　End Sub
　　Private Sub Form_Resize()
　　Picture1.Width = Me.Width * 0.94
　　Picture1.Height = Me.Height - (Command1(0).Height * 4 + 100)
　　Command1(0).Top = Me.Height - (Command1(0).Height * 2.5 + 100)
　　Command1(0).Left = Me.Width * 0.01
　　For i = 1 To 6
　　Command1(i).Top = Me.Height - (Command1(0).Height * 2.5 + 100)
　　Command1(i).Left = Command1(i - 1).Left + 1000
　　Next
　　XY
　　End Sub

Option Explicit
Dim i, j As Double
Private Sub Command1_Click()
Picture1.Font = "times new roman"
Picture1.FontItalic = True
Picture1.FontSize = 10
'设置字体
Picture1.Scale (-100, 100)-(100, -100)
'设置坐标轴标尺为100
Picture1.Line (-100, 0)-(100, 0)
Picture1.Line (95, 3)-(100, 0)
Picture1.Line (95, -3)-(100, 0)
Picture1.CurrentX = 90
Picture1.CurrentY = 15
Picture1.Print "x"
'画X轴及箭头
Picture1.Line (0, 100)-(0, -100)
Picture1.Line (3, 95)-(0, 100)
Picture1.Line (-3, 95)-(0, 100)
Picture1.CurrentX = 5
Picture1.CurrentY = 95
Picture1.Print "y"
'画Y轴及箭头
Picture1.CurrentX = -7
Picture1.CurrentY = 0
Picture1.Print "O"
'画原点
Command2.Enabled = True
Command3.Enabled = True
Command1.Enabled = False
End Sub

Private Sub Command2_Click()
For i = -100 To 100 Step 0.1
j = -0.1 * i * i + 6 * i - 10
Picture1.PSet (i, j), vbRed
Next i
'画y=-0.1x^2+6x-10的图像
End Sub

Private Sub Command3_Click()
For i = -100 To 100 Step 0.1
j = 100 * Sin(i * 3.1416 / 180)
Picture1.PSet (i, j), vbBlue
Next i
'画y=100sinx的图像
End Sub