ATAN（x）计算程序：

Dim Pi As Double

Private Sub CommandButton1_Click()

x = Sheet1.Cells(2, 1)

Pi = 3.141592654

If x = 0 Then

Sheet1.Cells(3, 1) = 0

Sheet1.Cells(3, 2) = 0

Exit Sub

End If

x1 = Abs(x)

If Abs(x) > 1 Then

x1 = 1 / Abs(x)

End If

y = x1

L = 0

jd = 0.0000000001

100 If L <= 100000 Then

y1 = y - (Tan(y) - x1) / (1 + (Tan(y)) ^ 2)

If Abs(y1 - y) > jd Then

y = y1

L = L + 1

GoTo 100

End If

End If

Sheet1.Cells(3, 1) = x / Abs(x) * y

If Abs(x) > 1 Then

Sheet1.Cells(3, 1) = x / Abs(x) * (Pi / 2 - y)

End If

Sheet1.Cells(3, 2) = L

End Sub

ASIN（x）计算程序：

Private Sub CommandButton2_Click()

x = Sheet1.Cells(5, 1)

y = x

L = 0

jd = 0.0000000001

100 If L <= 100000 Then

y1 = y - (Sin(y) - x) / Cos(y)

If Abs(y1 - y) > jd Then

y = y1

L = L + 1

GoTo 100

End If

End If

Sheet1.Cells(6, 1) = y

Sheet1.Cells(6, 2) = L

End Sub