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Homework Help: Help understanding question

  1. Feb 26, 2004 #1
    What is the following question asking?


    Prove that the determinant of the product of two general 2x2 matrces is the product of their determinants.

    What I think is that I should come up with two 2x2 matrices.
    1 2 2 3 12 15
    3 4 and 5 6 multiply them together and get 26 33

    The determinant of the product matrix is six. The determinat of the first matrix is -2 and the second one is -3. Multiply -2 times -3 and that is 6. So I proved that the determinant of the product of the two matrices is the product of their determinants.

    Is this right?
  2. jcsd
  3. Feb 26, 2004 #2
    here are the matrices

    1 2 (1)
    3 4

    2 3
    5 6 (2)

    12 15
    26 33 (product matrix)
  4. Feb 26, 2004 #3


    User Avatar
    Homework Helper

    You should probably be more general (let the elements be letters instead of numbers, and then show it). It looks like you've got the right idea, though.
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