编写VB程序,求数列的前n项之和:s=2/1+3/2+5/3+8/5+13/8…

编写VB程序,求数列的前n项之和:s=2/1+3/2+5/3+8/5+13/8…

Private Sub Command1_Click()
Dim n As Integer
n = InputBox("输入N值")
Dim a1 As Double
Dim a2 As Double
Dim a As Double
Dim sum As Double
a1 = 1
a2 = 1
For i = 1 To n
t = a1 + a2
a1 = a2
a2 = t
a = a2 / a1
sum = sum + a
Next i
Print "数列前" & n & "项和为" & sum
End Sub

这是数学问题哦,所以编程要有一定的数学知识的,要找出通项,在用循环做.
规律:
分母的n+2项是前两项的和,分子的n项是分母的n+1项,
先设置第一项和第二项的值,第三项就可以用公式计算了.

我暂时保留我的看法！

三个text , 一个button
Private Sub Command1_Click()
Dim i As Integer
Dim n As Integer
Dim dRet As Double

Dim mn As Double
Dim kn As Double
Dim t As Double
Dim s As String

n = Text1.Text

mn = 2
kn = 1
dRet = 0

For i = 1 To n
dRet = dRet + mn / kn
s = s & " + " & mn & "/" & kn
t = mn
mn = mn + kn
kn = t
Next i

Text2.Text = s
Text3.Text = dRet
End Sub

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