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Math Help - Matrix Inverse Proof

  1. #1
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    Matrix Inverse Proof

    Does anyone know how to prove this:

    If AB = I, then BA = I also. In other words prove that if B is the right inverse of A, then B is also the left inverse of A.

    Thanks.
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  2. #2
    Super Member girdav's Avatar
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    Re: Matrix Inverse Proof

    What are the tools you are allowed to use?
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  3. #3
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    Re: Matrix Inverse Proof

    I'm pretty much allowed to use anything.
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  4. #4
    Super Member girdav's Avatar
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    Re: Matrix Inverse Proof

    If AB=I, then B has full rank. We have B=(BA)B hence (I-BA)B=0. Show that it implies that I-BA=0.
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