Help with DeMorgans Law

Discussion in 'Homework Help' started by kantgetslicker17, Dec 7, 2005.

  1. kantgetslicker17

    Thread Starter New Member

    Dec 7, 2005
    6
    0
    [attachmentid=1019] Can somebody solve this problem in the attachment?

    I'm arguing with my teacher because she has a different answer from me, and I was able to prove to her with the truth table that I was correct. She's still saying that I did it wrong and there's no way to draw the truth table with DeMorgan's Law. Can somebody solve this problem so I can see what answer you get.

    My Answer: [attachmentid=1017]

    Teacher's answer: [attachmentid=1018]

    What my teacher did was that on the first step she break the long bar into the addition and into the multiplication.

    [attachmentid=1020]
     
  2. Brandon

    Senior Member

    Dec 14, 2004
    306
    0
    Her answer is wrong, here's your counter example to her solution.
    A=0, B=0, C=0
    Original Problem answer is 0
    not (0 * not ( 0 + not ( 0 ) ) + not ( 0 ) )=
    not ( 0 + not ( 0 ) )=
    not ( 1 ) = 0

    Her answer is 1
    not ( 0 ) + 0 * 0 + 0 * not ( 0 )=
    1 + 0 + 0= 1

    She made a mistake.. and of course she assumes you did it wrong.. Got to love that.
     
  3. kantgetslicker17

    Thread Starter New Member

    Dec 7, 2005
    6
    0
    Hey Brandon,

    THANKS FOR THE REPLY. We were going at it for like 30 mins, and it seem to me like she wouldn't admit that she was wrong. She kept trying to prove to me that her answer was right, and the way she proved it didn't make sense to me. The first step that she had done, I had told her she had violated the rules of algebra, her reply to me was "THIS IS NOT ALGEBRA, IT DOES NOT RELATE TO MATH!" That totally threw me off, I thought we were doing Boulean Algebra the whole time, which is math.

    I'll try to show her what you told me to do by substituting 0 for A.B.C. To show her, her solution is wrong.
     
  4. Brandon

    Senior Member

    Dec 14, 2004
    306
    0
    No problem..

    Its not typical algebra, its symbolic so it has different rules, but one rule never changes. If 1 equasion equals another, then they better both have the same answer given the same value.
     
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