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Vector algebra

  • Thread starter teclo
  • Start date
  • #1
117
0
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!
 

Answers and Replies

  • #2
Galileo
Science Advisor
Homework Helper
1,989
6
You're right. Did you copy the problem correctly?
 
  • #3
1,356
2
did you check the vectors out themselves?...? they are coplanar.
 
  • #4
117
0
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
 
  • #5
Galileo
Science Advisor
Homework Helper
1,989
6
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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