[ or (

[The Cat In The Hat]

What is the difference between [] and ()? How do you draw it on a graph? What do they each mean?
Thanks!

[whys]

[ denotes the inclusion of that particular point, and is indicated by a closed circle on a graph.
( denotes the exclusion of that particular point, and is indicated by an open circle on a graph.
Certain things, such as positive and negative infinity, must always be denoted by ( or ) as it can never be an included point.
See below:

The open circle means the point x = -3 on the graph is undefined (not included) and vice versa for the point x = 1, as it is denoted by a closed circle, meaning it is defined and included.

[The Cat In The Hat]

[ denotes the inclusion of that particular point, and is indicated by a closed circle on a graph.
( denotes the exclusion of that particular point, and is indicated by an open circle on a graph.
Certain things, such as positive and negative infinity, must always be denoted by ( or ) as it can never be an included point.
See below:
(Image removed from quote.)
The open circle means the point x = -3 on the graph is undefined (not included) and vice versa for the point x = 1, as it is denoted by a closed circle, meaning it is defined and included.

I didn't see this until now, because I didn't really understand the forums. However, thank you!! This is before my first SAC, so I'll probably copy a bunch of this into my bound reference
Thanks!!