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Homework Help: Vector Space

  1. Oct 17, 2007 #1
    1. The problem statement, all variables and given/known data

    Check to see if the (vector space) set of rational numbers is closed under addition and scalar multiplication

    2. Relevant equations

    The book says this holds for addition but fails for scalar multiplication.
    3. The attempt at a solution

    Im a little confused. You can add two of the same rational number like (1/2) and (1/2) and get an integer. Now your out of the vector space. Where is my logic failing me?
  2. jcsd
  3. Oct 17, 2007 #2


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    Integers are rationals: 2 = 2/1 = 4/2 = ...
  4. Oct 17, 2007 #3
    it's always the obvious. how funny
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