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Homework Help: Second order differential equation

  1. Nov 6, 2009 #1
    hello i need some help here!

    solve:

    x''+3x'+2x=1/(1+e^t)

    well ok the homogeneous solution is c1*e^t+c2*e^2t
    but how to determine the particular solution Xp!!!!!
     
  2. jcsd
  3. Nov 6, 2009 #2

    rock.freak667

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    Homework Helper

    Try using the variation of parameters method
     
  4. Nov 6, 2009 #3

    HallsofIvy

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    Science Advisor

    If the right hand side were a function of the kind one gets as a solution to a "homogenoous linear equation with constant coefficients"- polynomial, exponentian, sine and cosine, or combinations of those- then you could try "undetermined coefficients' but since it is not you will need to try "variation of parameters" as rock.freak667 suggested.
     
  5. Nov 7, 2009 #4
    thanks that worked,

    if you could give me a hint for this one

    t*x'=x+sqrt(x^2-t^2)
     
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