vb画tan函数图像If Combo1.Text = "tan" ThenFor x = -15 To 15 Step

答案补充：Cot函数这样修改即可.主要是你没有定义y的类型.至于fi*pi/180与fi有什么区别,那要根据你的fi单位而定.如果你是以角度输入的,那么应该加上＊pi／180,如果本身是以弧度输入的,就直接写fi即可.
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Private Sub Command1_Click()
Dim x As Single, y As Single
Picture1.Scale (-15, 15)-(15, -15)
For x = -15 To 15 Step 0.001
w = 1
y = 1 / (Tan(w * x))
Picture1.PSet (x, y), RGB(0, 255, 0)
Next x
End Sub
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建一个Command1,Picture1,Combo1.使用的时候,请先在Combo1中选择或者输入tan,然后单击按钮.
代码如下.
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Const pi = 3.14159265
Private Sub Command1_Click()
Dim x As Single, y As Single, w As Single, fi As Single
If Combo1.Text = "tan" Then
w = 1
fi = 0
Picture1.Scale (-15, 15)-(15, -15)
For x = -15 To 15 Step 0.001
y = Tan(w * x + fi)
Picture1.PSet (x, y), RGB(0, 255, 0)
Next x
End If
End Su