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Homework Help: Vector coplanar question

  1. Jan 15, 2010 #1

    jarman007

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    1. The problem statement, all variables and given/known data

    The value of n so that vectors 2i + 3j - 2k , 5i + nj + k and -i + 2 j + 3k may be coplanar?

    a)18 b)28 c)9 d)36


    2. The attempt at a solution

    I was not able to think of any step

    so please help
     
    jarman007, Jan 15, 2010
  2. jcsd
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  3. Jan 15, 2010 #2

    rl.bhat

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    Homework Helper

    Hi jarman007, welcome to PF.
    The vectors A, B and C are coplanar if A.(BXC) = 0
     
    rl.bhat, Jan 15, 2010
  4. Jan 15, 2010 #3

    jarman007

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    thanks and please check my solution

    BxC = 10k -15j + nk + 3ni + j +2i = (3n+2)i -14j + (10+n)k


    A.(BxC)=6n+4-42-20-2n=0

    therefore n = 58/4
     
    jarman007, Jan 15, 2010
  5. Jan 15, 2010 #4

    rl.bhat

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    BxC = 10k -15j + nk + 3ni + j +2i = (3n+2)i -14j + (10+n)k
    This calculation is wrong.
    Check i and j coefficients. My answer is 18.
     
    rl.bhat, Jan 15, 2010
  6. Jan 16, 2010 #5

    jarman007

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    thanks

    got the answer
     
    jarman007, Jan 16, 2010
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