Interval notation is a method of writing down a set of numbers. Consider a variable x and two numbers A and B.
- (A, B) is used to denote A<x<B
- [A, B) is used to denote A<=x<B
- [A, B] is used to denote A<=x<=B
- (A, B] is used to denote A<x<=B
Using the rules listed above the interval notation that represents the set of all numbers greater than or equal to 5 and less than 12 is option 1.
The correct interval notation is [5, 12) which is option 1.
Answer (1) is correct. The square bracket, [, indicates that 5 is included in the set while the parenthesis means that 12 is not included in the set.