1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Set A consisted of all even natural numbers

  1. Feb 14, 2004 #1
    If set A consisted of all even natural numbers (i.e. 2, 4, 6...) and set B consisted of all odd natural numbers (i.e. 1, 3, 5...), then what is the result set of:

    A intersection B

    Would it just be the empty set since no two natural numbers can be even and odd?
  2. jcsd
  3. Feb 14, 2004 #2


    User Avatar
    Science Advisor

    Yes, exactly. An element is in "A intersect B" if and only if it is in both A and B. There is no integer that is "both" even and odd and so, in this case, A intersect B is empty. That's a very common occurence. In fact there's a special name for it: the two sets are "disjoint".
  4. Feb 14, 2004 #3
    Yes it should be null set
  5. Feb 14, 2004 #4
    I was kind of nervous when I was taking a test on this material because the question was to list at least three elements that were in the following sets, and one of those following sets was A intersection B. Guess it had to be a typo on the test. Hopefully I didn't read the question wrong. If I remember right, I'm very sure that A and B were natural number sets. Ah well.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook