почему программа не считает? (visual basic)

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim x As Integer
Dim y As Double
x = Val(TextBox1.Text)
Select Case x
Case x >= 0, x < 1
y = Math.Abs(Math.Sin(Math.Pow(x, 2) / 1.5) - 2) + 11 * Math.Cos(1.6 * x - 1)
Case x >= 1
y = 13.4 * Math.Sin(-1.26) * Math.Cos(Math.Abs(x / 7.5))
End Select
MsgBox(y)
End Sub
End Class