Private Sub Command1_C1ick ( )
Dim a(9) As Integer
a(9)=Val(Text1.text)
For i=8 to 1 step -2
a(i)=a(i+1)/2
Next i
Text2.text=str(a(i))
End Sub
如图:⊙O的直径AB=12,AM和BN是它的两条切线,DE切⊙O于E,交AM于D,交BN于C,设AD=X,BC=Y,求Y与X的函数关系式,并画出它的大致图象.