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Linear algebra question

  1. Mar 2, 2009 #1
    Linear algebra question....

    Hello again!

    Ok...so if I let A =

    [0 1 0 ]
    [1 1 -2]
    [2 3 -3]

    How would I find A^-1? Is that the notation for inverse?

    Also, could I express A^-1 as a product of at most five elementary matrices? What does this mean exactly?

  2. jcsd
  3. Mar 2, 2009 #2


    User Avatar
    Homework Helper

    Re: Linear algebra question....

    Elementary matrices are the representation of elementary operations. So see if you can get from the identity to A with five or fewer operations. Hint may help to instead see if you can go from A to I in five steps.

    Elementary operations are
    -interchange two rows
    -multiply a row by a nonzero value
    -add a multiple of a row to another
  4. Mar 3, 2009 #3


    User Avatar
    Science Advisor

    Re: Linear algebra question....

    Use row reduction to reduce A to the identity matrix. The elementary matrices corresponding to those row operations will multiply to give A-1.
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