Question

用VB迭代法求某个数的平方根

题目：用迭代法求某个数的平方根。 已知求平方根的迭代公式如图：

算法思想：对于一个问题的求解x，可由给定的一个初值x0，根据某一
x 迭代公式得到一个新的值x1，这个新值x1比初值x0更接近要求的值x；
再以新值作为初值，即：x1→x0,重新按原来的方法求x1,重复这一过和 直到|x1-x0|<ε(某一给定的精度,如0.00001)。此时可将x1作为问题的解。

'-------------------------------------------------
'注意：请在指定的事件内编写代码。
'-------------------------------------------------

Private Function Fsqrt(a As Single) As Single

'********** Program *********

'********** End *************

End Function

Private Sub Form_Load()
Show

Print Fsqrt(45)

WWJT

End Sub

Private Sub WWJT()

Dim i As Integer
Dim s As String
Dim l As Single
Dim d As Double
Dim a(10) As String

Dim fIn As Integer
Dim fOut As Integer
fIn = FreeFile
Open App.Path & "\in.dat" For Input As #fIn
fOut = FreeFile
Open App.Path & "\out.dat" For Output As #fOut

For i = 1 To 10
Line Input #fIn, a(i)
l = Val(a(i))
Print #fOut, Fsqrt(l)
Next

Close #fIn
Close #fOut

End Sub
Come on！

Answer 1

Dim
x0
As
Single
Do
If
x0
=
0
Then
x0
=
InputBox("请输入初值")
Else
x0
=
a
End
If
a
=
Sqr(x0)
Loop
Until
Abs(a
-
x0)
<
0.0000001
End
Function

Answer 2

Dim x0 As Single
Do
If x0 = 0 Then
x0 = InputBox("请输入初值")
Else
x0 = a
End If
a = Sqr(x0)

Loop Until Abs(a - x0) < 0.0000001

End Function

Answer 3

公式在哪?