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Homework Help: Boolean algebra

  1. Feb 19, 2007 #1
    1. The problem statement, all variables and given/known data

    1) Simplify the following Boolean expression:
    Y = ABCD – ABD


    2. Relevant equations



    3. The attempt at a solution

    I simplified it in the following way:
    Y = ABCD – ABD. (C + 1)
    = - ABD
    But the answer given in my book is ABD.
     
  2. jcsd
  3. Feb 23, 2007 #2
    Typos are possible

    Could be a typo in the back of the book. In my Discrete Math we are finding almost 20 errors per section. =o) Contact your teacher?
     
  4. Feb 25, 2007 #3
    Could you specify which textbook and which page? Thanks.

    Boolean algebra deals solely in ones and zeroes. It has only three operators: addition, multiplication and negation. There can be no negative numbers. Namely, -1 is not an allowed number, so the concept of subtraction is meaningless is Boolean algebra.

    Having said that, Y= ABCD – ABD has either a misprint – instead of +. In this case,
    Y= ABCD + ABD = ABD(C+1)=ABD(1)=ABD

    Or, possibly, – is given some special meaning.
     
  5. Mar 5, 2007 #4
    Sorry for the delayed reply. I was busy with my exams. It is a book by an Indian author. Basic Electronics by B.L.Theraja. I think u r right.The question should have been,
    Y = ABD - ABCD
    Isn't it?
     
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