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Homework Help: Check the working ( set )

  1. Nov 17, 2003 #1
    using algebraic laws of sets, show that, for any set A and set B that

    ( A U B ) [inter] ( A U B' ) = A


    this is my working

    ( A U B ) [inter] ( A U B' )

    = A U ( B [inter] A ) U ( B [inter] B' )

    = ( A U B ) [inter] ( A U A )

    = ( A U B ) [inter] A

    = A U ( B [inter] A )

    = A ( shown )


    i think this working is wrong. is there other way better than this?
     
  2. jcsd
  3. Nov 17, 2003 #2
    denian,
    I think the 1st step should be

    ( A U B ) [inter] ( A U B' )

    = A[inter]A U A[inter]B' U B[inter]A U B[inter]B'
     
  4. Nov 17, 2003 #3
    ok. i dont even know we can expand it that way.
    thank you.
     
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