выбивает ошибку при запуске макроса sub on function not defined

Public Sub Pryklad()

    Dim z As Double, c As Single, d As Single, e As Long, x As Long, a As Long

    x = Val(InputBox("12.2"))

    c = Val(InputBox("8.52"))

    a = Val(InputBox("2"))

    d = Val(InputBox("0.5"))

    e = Val(InputBox("2.71"))

    z = Pow((Sqr(ax + b) / (c + dx) + Sin(x) / Cos(x)), 2 / 3) - Pow(e, 2 * x)

    MsgBox ("Результат" & Str(z))

End Sub