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Homework Help: Vector algebra

  1. Sep 4, 2005 #1
    so, i'm trying to determine if the vectors
    2,1,-1
    1,1,0
    2,-1,3

    are coplanar. i take the triple product, finding the determinant of the matrix. it seems to be non-zero, but the answer key insists these are coplanar. am i wrong, or perhaps the book? any input would be appreciated!
     
  2. jcsd
  3. Sep 4, 2005 #2

    Galileo

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    You're right. Did you copy the problem correctly?
     
  4. Sep 4, 2005 #3
    did you check the vectors out themselves?...? they are coplanar.
     
  5. Sep 4, 2005 #4
    coplanar means that they all exist on the same plane, right? i just made a vypthon program to draw all of the vectors as they are starting from the origin. it looks to me like the definitely span a parallelpiped, but i could certainly be wrong... now i'm even more confused
     
  6. Sep 5, 2005 #5

    Galileo

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    Well, the determinant is 6, so the three vectors are linearly independent. Since two of the vectors span a plane and the third is not a linear combination of the former two it does not lie in the same plane.
     
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