practice8_6.frm

深圳大学的vb上机与教学的课件

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "用牛顿迭代法求解"
   ClientHeight    =   2895
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5100
   LinkTopic       =   "Form1"
   ScaleHeight     =   2895
   ScaleWidth      =   5100
   StartUpPosition =   2  '屏幕中心
   Begin VB.CommandButton Command1 
      Caption         =   "求解"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   1800
      TabIndex        =   0
      Top             =   2160
      Width           =   1215
   End
   Begin VB.Label Label2 
      AutoSize        =   -1  'True
      Caption         =   "在X=0附近的一个近似根"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   15
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   300
      Left            =   600
      TabIndex        =   3
      Top             =   1440
      Width           =   3330
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      Caption         =   "用牛顿迭代法求方程："
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   15
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   300
      Left            =   600
      TabIndex        =   2
      Top             =   240
      Width           =   3150
   End
   Begin VB.OLE OLE1 
      BackStyle       =   0  'Transparent
      BorderStyle     =   0  'None
      Class           =   "Equation.3"
      Height          =   495
      Left            =   480
      OleObjectBlob   =   "practice8_6.frx":0000
      SizeMode        =   1  'Stretch
      TabIndex        =   1
      Top             =   720
      Width           =   4455
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Function F(X0, N)
   N = 0   ' N用于保存迭代次数
   X = X0
   Do
      FX = X ^ 5 + 2 * X ^ 3 - X ^ 2 + X + 1  ' 求f(x)
      FX1 = 5 * X ^ 4 + 6 * X ^ 2 - 2 * X + 1 ' 求f'(x)
      X1 = X                  ' 保存当前根
      X = X - FX / FX1        ' 求下一个根
      N = N + 1
   Loop Until Abs(X1 - X) < 0.0000001
   F = X
End Function
Private Sub Command1_Click()
    MsgBox "方程的根为：" & Str(F(0, N))
    MsgBox "迭代次数为" & Str(N)
End Sub