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Homework Help: Matrix Proof

  1. Sep 23, 2012 #1
    If A and B are n × n matrices, when does
    (A + B)(A − B) = A^2 − B^2?

    I guess I start out by expanding?

    A^2 - BA-B^2+BA=0

    Thus AB=BA in order for that to work?
     
  2. jcsd
  3. Sep 23, 2012 #2

    jbunniii

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    Correct.
     
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