If A = {positive integers} and B = {…,−4, −3, −2, −1} what is A ∩ B?

{ }

{…, −3, −2, −1, 1, 2, 3, …}

{1, 2, 3, 4, …}

{…−3, −2, −1}

Question

If A = {positive integers} and B = {…,−4, −3, −2, −1} what is A ∩ B?

{ }

{…, −3, −2, −1, 1, 2, 3, …}

{1, 2, 3, 4, …}

{…−3, −2, −1}

anonymous · Answer

Whoa, set theory :D Glad to see a hard level question.

A ∩ B means the set that contains all those elements that A and B have in common.

so the resultant set is all numbers that A and B have in common, which is none.

anonymous · Answer

so its a?

anonymous · Answer

Yes, since neither A and B contain any identical elements, their intersection is the empty set, denoted by
$$\emptyset, \text{ or simply } \{\}$$

anonymous · Answer

okay thanks(: want to help me on some more?

anonymous · Answer

Feel free to ask another question separately from this thread. More people are likely to help you that way.