用以下公式求f(x)的值。当通项的绝对值小于10^-7时停止计算,x的值由键盘输入。
f(x)=a1x1-a2x2+a3x3-…+(-1)n+1anxn+… |X|
1
其中 a1=1,a2=2,an= ,n=3,4,5…
Option Explicit
Private Sub Commandl_Click()、
Dim x As Single,fx As Single
Dim a As Single,a1 As Single,a2 As Single
Dim t As Single
a1=l:a2=2
x=text1
If () Then
MsgBox("x必须在-1---1之间")
ExitSub
End If
fx=a1*x-a2*x*x
t=(-1)*x*x
DO
a=1/(al+a2)
t=(-1)*x*x
fx=()
al=a2
()
Loop Until Abs(a*t)<0.0000001
Text2=fx
End Sub