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Matrix multiplication - is this plausible?

  1. Apr 8, 2014 #1
    say X = (AB) (B-1 C)

    B-1 = B inverse (B B-1 = B-1 B = I)

    then can i write X = AC?

    just having a brain fart moment. i would appreciate a speedy response, cheers.
     
    Last edited: Apr 8, 2014
  2. jcsd
  3. Apr 8, 2014 #2

    Simon Bridge

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  4. Apr 9, 2014 #3
    nah i just needed someone to verify that. thanks :)
     
  5. Apr 9, 2014 #4

    Simon Bridge

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    No worries.
     
  6. Apr 9, 2014 #5

    HallsofIvy

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    The "properties of matrix multiplication" that Simon Bridge referred to that are needed here are specifically the "associative law" and the definition of "inverse", that [itex]BB^{-1}= I[/itex]

    By the associative law, [itex](AB)(B^{-1}C)= A(BB^{-1})C[/itex] and then [itex]BB^{-1}= I[/itex] gives [itex]A(I)C= AC[/itex].
     
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