VB sin(x)近似值
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【例】用以下公式求sin(x)的近似值,当最后一项小于10-7时停止计算,X的值由键盘输入。

VB sin(x)近似值

分析:用FuHao表示(-1)n-1

   用JieCheng表示(2n-1)!

   用FeiZi表示x2n-1

   用Term表示每一项的值,则Term=FuHao*(FeiZi/JieCheng)

   SinX表示sin(x)的近似值

   循环初始条件:SinX = 0,N = 1

   循环终止条件:Term<0.0000001

程序源码:

Option Explicit
Private Sub Form_Click()
   Dim SinX As Double, JieCheng As Double, Term As Double, FeiZi As Double
   Dim X As Integer, I As Integer, N As Integer, FuHao As Integer
   SinX = 0: N = 1
   X = Val(InputBox("请输入X的值:"))
   Do
      FuHao = (-1) ^ (N - 1)
      JieCheng = 1
      For I = 1 To 2 * N - 1
         JieCheng = JieCheng * I
      Next I
      FeiZi = X ^ (2 * N - 1)
      Term = FuHao * (FeiZi / JieCheng)
      SinX = SinX + Term
      N = N + 1
   Loop Until Term < 0.0000001
   Print "sin(" & X & ")≈" & SinX
End Sub

转载自:http://www.longziyong.cn/post/335.html

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