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Homework Help: Pivot Question

  1. Feb 22, 2006 #1
    Hi

    I got simple question. How is it that determain if a column in matrix is a pivot column?

    Sincerely

    Fred
     
  2. jcsd
  3. Feb 22, 2006 #2

    NateTG

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    Are you asking about gaussian reduction, the simplex method, or something else?
     
  4. Feb 22, 2006 #3
    What I'm asking given a matrix

    A= [[1,2,2,0,1,1][0,i,0,0,1,2][0,0,0,0,i,0][0,0,1,2,2i]]


    Which in echelonform gives

    A ~[[1,2,2,0,1,1][0,1,0,0,-i,-2i][0,0,1,2,0,2i][0,0,0,0,1,0]]

    My question is the pivot column of this matrix aren't they

    column 1,2,5,6 ??

    Since the definition a pivot position is is the column where there is a non-zero entry above a zero entry??

    Best Regards
    Mathboy20
     
  5. Feb 22, 2006 #4

    NateTG

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    For row echelon form, the pivot columns where there is a non-zero value to the right of leading zeros.

    In the example you give, the pivot columns would be 1,2,3, and 5.
     
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