Private Sub ApproxVerify()
    'Test the Approx function.

    Debug.Assert Approx(0.000000000000005, 0) ' 5E-15

    Debug.Assert Approx(0.00000000000001, 0) = False ' 1E-14
    Debug.Assert Approx(0.00000000000005, 0) = False ' 5E-14

    Debug.Assert Approx(1.00000000000001, 1) = True ' 1 + 1E-14
    Debug.Assert Approx(1, 1.00000000000001) = True ' 1 + 1E-14
    Debug.Assert Approx(1.00000000000005, 1) = False ' 1 + 5E-14
    Debug.Assert Approx(1, 1.00000000000005) = False ' 1 + 5E-14

    Debug.Assert Approx(13, 13.0000000000001) ' 13 + 1E-13
    Debug.Assert Approx(13.0000000000001, 13) ' 13 + 1E-13

    Debug.Assert Approx(13, 13.000000000001) = False ' 13 + 1E-12
    Debug.Assert Approx(13.000000000001, 13) = False ' 13 + 1E-12

End Sub