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Homework Help: Matrix, solve, parametres

  1. Oct 28, 2014 #1
    1. The problem statement, all variables and given/known data
    hi. i have a linear equation with parameters that i am trying to solve. unknowns are x, y and z.
    (12-3t)x + 2y +2z =2
    x +0*y +2z =0
    12x + (2-t)y + (2-t)z = 12

    i am using a matrix-approach with Gaussian-elimination, and my results (for values of t which allows for a specific solution) seem reasonable, but the the variables depend on t. is this correct, or will the answers be without the parameter t even if t is not specified. i believe i have seen a similar problem in one of my books where the solution is without the parameter t.

    2. Relevant equations
    am i getting it wrong?

    3. The attempt at a solution
    x= -(2t+20)/(3t2t), y= -(37t-110)/(3t2t), z= (t+10)/(3t2t)
    Last edited by a moderator: Oct 28, 2014
  2. jcsd
  3. Oct 29, 2014 #2


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    I think you're doing just fine. For every value of t (*) you have a different set of equations, so it's no wonder t appears in the solution.

    (*) for t=0 you get conflicting equations, so it's not surprising there is no answer for x,y,z.
  4. Oct 31, 2014 #3


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    I am puzzled as to why you are writing "[itex]t^2t[/itex]" rather than "[itex]t^3[/itex]". Am I misunderstanding what you mean?
  5. Nov 1, 2014 #4


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    Check the denominator. I think you just copied it wrong.
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