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Basic Matrix Question

  • 21-05-2010 12:31pm
    #1
    Smythe
    Registered Users, Registered Users 2 Posts: 434 ✭✭


    Find the matrix AB

    A
    3 2
    6 5

    B
    -1 3
    4 1

    I got an asnwer of:

    AB
    5 11
    14 24

    Though in the notes which were provided by our teacher the answer is:

    AB
    5 11
    3 23


    Have I calculated it incorrectly?

    Thank you :)


Comments

  • #2
    TouchingVirus
    Registered Users, Registered Users 2 Posts: 8,584 ✭✭✭TouchingVirus


    I think you both might be wrong, you have 3 elements correct but have another look at your 24


  • #3
    sponsoredwalk
    Registered Users, Registered Users 2 Posts: 3,038 ✭✭✭sponsoredwalk


    My latex matrix isn't working for some reason :(

    [3,2]|[-1,3]
    [6,5]|[_4,1]

    Take the row of the first matrix & multiply it by the column of the second matrix;

    [(3x-1 + 2x4),(3x3 + 2x1)]
    [(6x-1 + 5x4),(6x3 + 5x1)]

    [_5,11]
    [14,23]

    Give out to your teacher ;)


  • #4
    Smythe
    Registered Users, Registered Users 2 Posts: 434 ✭✭Smythe


    Ah, thanks very much.

    Yes I made a slip in calculating the last one.

    That's great, thanks! :)


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