Stage 19 · Sets & Intervals — the Language of Functions
19.5.2 Open and Closed Intervals
19.5 Intervals and Neighborhoods: Sets on the Number Line
Point 2 of 5
19.5.2 Open and Closed Intervals
Core ideaBrackets tell you whether the endpoints count: [ ] includes them, ( ) leaves them out, written [1,5] or (1,5).
Module goal. Carry the language of sets onto the number line, using intervals and neighborhoods to capture continuous ranges of numbers neatly — a direct route to the domain of a function