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Matrix/Linear Algebra Quickie...

Discussion in 'Off-Topic' started by 5Ws, Apr 13, 2005.

  1. 5Ws

    5Ws Banned

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    Matrix/Linear Algebra Quickie...

    If A is nxn, det(-A) = det(A) only when n is even right?
    and if n is odd, det(-A) = -det(A) right?
    Kind of a crucial step for a proof I had to do on today's test.
     
  2. AeroJonesy

    AeroJonesy IncGamers Member

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    Yeah, I'm pretty sure you're right, but not 100%. It's been awhile since I went over those rules.

    edit: In my head it makes sense, since when you are taking the determinant of an even matrix, you are always taking products of even amounts of numbers (4 things getting multiplied in a 4x4, etc) so the negative signs will cancel out.
     
  3. 5Ws

    5Ws Banned

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    OK, found the thing in the book:
    A-nxn
    det(kA)=k to the nth power times det(A).
    Therefore in our case, k=-1, so yeah, I think I got it right, whoohoooo!
     
  4. SuggestiveName

    SuggestiveName IncGamers Member

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    Yes, without double checking my book I'm like 96% sure you are correct. God I long for the days of linear algebra.... *goes back to pondering 3-manifolds* Mmmm...topology in 4 dimensions, yummy.
     
  5. Isolde212

    Isolde212 Banned

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    Here we go with the sexy math talk again...
     
  6. SuggestiveName

    SuggestiveName IncGamers Member

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    No more mocking math majors or so help me god I will rigorously prove that canada does not exist. Then you dissapear in a puff of logic.
     
  7. Isolde212

    Isolde212 Banned

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    I wasn't mocking. I honestly think math geeks are sexy. It's wierd. I think my obsession developed when I went to university and most of the guys there were either engineering or math students. For once someone was talking about something I just couldn't understand. I find it fascinating.
     
  8. SuggestiveName

    SuggestiveName IncGamers Member

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    It never fails...all the girls that dig math geeks are always taken.
     
  9. AeroJonesy

    AeroJonesy IncGamers Member

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    I hear you on that one. :(
     
  10. 5Ws

    5Ws Banned

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    OMGZ, a lapdance-less OTF??? I cannot imagine!
     

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