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Homework Help: Have complimentary, can't get the particular

  1. Mar 1, 2012 #1
    1. The problem statement, all variables and given/known data

    d4y/dx4 - a4y = eax

    I have found the complimentary to be

    Y(x)c = C1eax + C2e-ax + C3Cos(ax) + C4Sin(ax)

    I can't seem to get get the particular. I've tried letting Y(x) = Aeax
    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 1, 2012 #2
    That gives me Aa^4exp(ax) - Aa^4exp(ax) = exp(ax) :(
     
  4. Mar 1, 2012 #3

    ehild

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    Try Y=Ctexp(ax).

    ehild

    edit: "t" is a typo: It should be Y= Cxexp(ax)
     
    Last edited: Mar 2, 2012
  5. Mar 1, 2012 #4

    HallsofIvy

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    ehild means [itex]xe^{ax}[/itex], not [itex]te^{ax}[/itex].
     
  6. Mar 2, 2012 #5

    ehild

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    Homework Helper

    Thank you, I edited it.

    ehild
     
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