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Homework Help: Proof on matrix multiplication

  1. Sep 12, 2010 #1
    1. The problem statement, all variables and given/known data
    A is an mxn matrix and C is a 1xm matrix. Prove that CA=Sum of (C sub j)*(A sub j) from j=1 to m.
    Where A sub j is the jth row of A

    Sorry for the messy problem statement, I couldn't figure out the summation notation on here.

    2. Relevant equations

    3. The attempt at a solution
    I set (C sub j)*(A sub j)=D sub j
    I then tried to manipulate it towards something, but I made no progress, thanks for any help you can give.
  2. jcsd
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