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Homework Help: PLEASE HELP a matrix proof

  1. Oct 23, 2006 #1

    j3n

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    PLEASE HELP!! a matrix proof..

    Hey!

    I really need help with this question if possible.

    Let Q be an n x n matrix with each entry = 1
    Let I be the n x n identity matrix
    let H = Q-n*I
    show that det(H) = 0

    (hint: think of row reducing H)

    Thanks a lot,
    j3n
     
  2. jcsd
  3. Oct 23, 2006 #2

    HallsofIvy

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    Science Advisor

    The hint pretty much tells you what to do. This might help: What is the sum of each column?
     
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