Question

HELP!!!
Which interval notation represents the set of all real numbers greater than 2 and less than or equal to 20?

1. (2,20) 2. (2,20] 3. [2,20) 4. [2,20]

Answer 1

( or ) means the end value is not included (or just greater than/less than, NOT equal to). Eg (0, 10) means x is greater than zero and less than 10.

[ or ] means the end value is included. Eg [0, 10] means x is greater than or equal to zero, and less than or equal to 10.

(0, 10] means x is greater than 0 (but not equal to), and less than or equal to 10.

[0, 10) means x is greater than or equal to zero, and less than 10 (but not equal to).



How would you show "greater than 2 and less than or equal to 20?"
note that "greater than" means you need a ( and less than or equal to means you need a ]

Answer 2

so it's (2,20] ? @agent0smith

Answer 3

Correct.