定积分我这么做的，正确吗？
Private Sub Command1_Click()
Dim i As Single
Dim s As Single
For i = 1 To 17 Step 0.01
s = ((2 * i ^ 3 + Sqr(3) * Exp(-1.6 * i)) + (2 * (i + 0.01) ^ 3 + Sqr(3) * Exp(-1.6 * (i + 0.01)))) * 0.01 / 2
Text1.Text = Val(Text1.Text) + s
Next i
End Sub

Option Explicit
'一个CommandButton，三个Label，注意声明用双精度
Private Sub Command1_Click()
Dim x
#, y#
, yy
#, Astep#

Astep = 0.00001
For x = 1 To (17 - Astep) Step Astep '几何法
y = y + (2 * x ^ 3 + Sqr(3) * Exp(-1.6 * x)) * Astep
Next x
yy = (0.5 * 17 ^ 4 + (-Sqr(3) / 1.6) * Exp(-1.6 * 17)) - (0.5 + (-Sqr(3) / 1.6) * Exp(-1.6)) '解析法
Label1.Caption = "几何法结果:" & y
Label2.Caption = "解析法结果:" & yy
Label3.Caption = "误差为:" & (y - yy)
End Sub