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Linear algebra: Determinant

  1. Oct 14, 2010 #1
    1. The problem statement, all variables and given/known data

    Evaluate the following determinant by expressing the matrix in upper triangular form.

    2. Relevant equations

    row operations.

    3. The attempt at a solution

    http://img707.imageshack.us/img707/6379/scan0001ug.jpg [Broken]
    [PLAIN]http://img707.imageshack.us/img707/6379/scan0001ug.jpg [Broken]

    I want to know what I did wrong there cause I cant figure it out
    the calculator shows a different answer.
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 14, 2010 #2


    Staff: Mentor

    In your 4th (or so) step, you replaced row 2 by 1/2 itself. Replacing a row by a nonzero multiple of itself is one row operation that changes the value of the determinant. The other row operation that does this is swapping two rows.

    The correct value of the determinant is -17.
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