Question

what is the first element of (2,5)?

Answer 1

Answer:

4and 10....

....

..

.

..m

.m.

..

Answer 2

Since interval notation like (a, b) is used for real numbers, you can't really determine the first element of such set. It's because (2, 5) denotes all real numbers between 2 and 5. Theoretically, its first element should be the real number exactly after 2 but you can't determine which number is exactly after 2 because between 2 and 3 there can be infinite real numbers.