阅读下述程序,导出指定变量的计算公式。
Option Base 1
Private Sub Command 1_Click()
Dim X As Single, PS As Single, PD As Single, A(), B()
A= Array(-1.2,1.7,2.5,3.3,3.5)
B=Aray(0.8,0.6,0.1,-1.1,-4.1)
X= Val( Text 1. Text)
PS=PP(X, A,5,1)
PD=PP(X, B, 4, 2)
Print X, PS, PD
End Sub
Private Function PP(X As Single, B() As Variant, By Val N As Integer, By Val TT As Integer) As Single
Dim I As Integer, K As Integer
PP=0.0
For I=1 To N
K=N-I+1
PP=PP* X*X+B(K)
Next I
If TT>1 Then PP=PP*X
End Function
其中PS、PD的计算公式为?