VB中的 e^x ≈ 1 + x / 1! + x2 / 2! + x3 / 3! + … + xn / n!

VB程序如下:
Public Function exmi(x!,n%) As Single
Dim i%,t!
exmi=1
t=1
For i=1 To n
t=t * x / i
exmi=exmi+t
Next i
End Function
Private Sub Form_click()
Dim a!,b!,x!,n%
x=Val(Text1.text)
n=Val(Text2.text)
a=exmi(x,n)
b=exmi(-x,n)
Text3.text=(a+b)/2
End Sub

你这个应该有一个最小值的范围

Private Sub Command1_Click()
Dim n As Integer, t As Single
Dim x As Integer
Dim s As Single, y As Single
t = 1: s = 1: y = 1
x = Text1.Text
Do
n = n + 1
t = x ^ n
s = s * n
y = y + t / s
Loop While t / s >= 10 ^ (-5)
Text2.Text = y - t / s

End Sub

自己建2个text文本框和1个命令按钮！