Square brackets, specifically [ and ], are used for closed intervals.
According to the reference, interval notation uses open brackets () for < or > and closed brackets [] for ≤ and ≥. This means that a closed interval includes the endpoint, while an open interval does not.
For example:
- The interval
[4, 6]represents all numbers between 4 and 6, including 4 and 6. This is a closed interval. - The interval
(0, 2)represents all numbers between 0 and 2, excluding 0 and 2. This is an open interval. - The interval
[4, 6]U(0, 2)combines a closed and an open interval, representing all numbers between 4 and 6 (inclusive) and all numbers between 0 and 2 (exclusive).
