Hallo zusammen,

ich möchte gerne den Effektivzins einer Anleige mithilfe des Newtonverfahrens berechnen.

Dazu habe ich folgenden VBA-Code, der noch fehlerhaft ist, programmiert. Leider kann ich den Fehler nicht finden.

Ich hoffe, dass Ihr mir weiterhelfen könnt.

Besten Dank im Voraus.

lg

Fabi

Option Explicit
Option Base 1

Sub newtonverfahren()

Dim wb As Workbook
Set wb = ThisWorkbook
Dim i_new As Variant, ne As Single, c As Single, pv As Single, T As Single, n As Single, delta As Single, i As Single, bw As Single
Dim bw2 As Single, cf As Single, cf2 As Single, f As Single


ne = 100
c = 0.075
i = 0.1     'Startwert
pv = 103
T = 30
delta = 0.0000001

Do
i = i_new
i_new = i - f / bw2

For n = 1 To T
    If n < T Then
        cf = (ne * c) / (1 + i) ^ n
    Else: n = T
        cf = ((1 + c) * ne) / (1 + i) ^ n
    End If
bw = bw + (pv - cf)

f = pv - bw

Next n

For n = 1 To T
    If n < T Then
        cf2 = n * (ne * c) / (1 + i) ^ (n + 1)
    Else: n = T
        cf2 = n * ((1 + c) * ne) / (1 + i) ^ (n + 1)
    End If
bw2 = bw2 + cf2

Next n

Loop Until Abs(i_new - i) < delta

MsgBox "Effektivzins:   " & i_new

End Sub