Results 1 to 5 of 5

Math Help - set related question ... need confirmation if I am doing this correct :-)

  1. #1
    Junior Member
    Joined
    Jun 2011
    Posts
    66

    set related question ... need confirmation if I am doing this correct :-)

    I need some help with understanding this question as well:

    ==================================== A B = {x|x A x B}
    A = {a, b, e, f}
    B = {b, d, g, f, a}

    Match the following to the correct answers.
    A B = ?
    B A = ?

    Answers:
    a. {a, b, f}
    b. {a, b, e, f}
    c. {d, g}
    d. {e}
    ====================================


    What I understand here is that x has elements in A and that those elements are not part of B.
    So when we do A - B the correct answer is: c. {a, b, f}


    and B - A would be: c. {d, g}
    Is this correct?

    Thanks,
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor FernandoRevilla's Avatar
    Joined
    Nov 2010
    From
    Madrid, Spain
    Posts
    2,162
    Thanks
    44

    Re: set related question ... need confirmation if I am doing this correct :-)

    Quote Originally Posted by iwan1981 View Post
    A B = {x|x A x B} A = {a, b, e, f} B = {b, d, g, f, a} Match the following to the correct answers. A B = ? B A = ?

    A-B=\{e\} and B-A=\{d,g\}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jun 2011
    Posts
    66

    Re: set related question ... need confirmation if I am doing this correct :-)

    Quote Originally Posted by FernandoRevilla View Post
    A-B=\{e\} and B-A=\{d,g\}
    How did you get this answer ... and what was I doing wrong?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Dec 2009
    From
    1111
    Posts
    872
    Thanks
    3

    Re: set related question ... need confirmation if I am doing this correct :-)

    Quote Originally Posted by iwan1981 View Post
    I need some help with understanding this question as well:

    ==================================== A B = {x|x A x B}
    A = {a, b, e, f}
    B = {b, d, g, f, a}

    Match the following to the correct answers.
    A B = ?
    B A = ?

    Answers:
    a. {a, b, f}
    b. {a, b, e, f}
    c. {d, g}
    d. {e}
    ====================================


    What I understand here is that x has elements in A and that those elements are not part of B.

    No. x is not a set. It represents a element in A-B. So your statement should be corrected as, "A-B includes all the elements in A which are not in B".

    So when we do A - B the correct answer is: c. {a, b, f}

    This is incorrect as a,b and f are in B.

    and B - A would be: c. {d, g}

    Is this correct?

    Correct

    Thanks,
    .
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Jun 2011
    Posts
    66

    Re: set related question ... need confirmation if I am doing this correct :-)

    I understand now ... that's why the ∉ (elements not in) comes into play ... I should've seen that one :-)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 12th 2009, 08:52 PM
  2. Log from earlier question, just need confirmation!
    Posted in the Pre-Calculus Forum
    Replies: 6
    Last Post: November 20th 2008, 10:21 AM
  3. confirmation in regards to this question
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 4th 2008, 02:44 PM
  4. Confirmation for related rates problem.
    Posted in the Calculus Forum
    Replies: 1
    Last Post: April 3rd 2007, 05:21 PM
  5. Question on Sets - Need confirmation
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: June 22nd 2006, 01:16 AM

/mathhelpforum @mathhelpforum