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How to find Particular integral of this differential eq:

  1. Mar 28, 2012 #1
    1. The problem statement, all variables and given/known data
    Solve the following differential equation

    y'''-3y''+2y' = e^x/(1+e^(-x))


    2. Relevant equations



    3. The attempt at a solution

    first i find the complementary function i-e
    Yc= C1 e^x + C2 e^(1+√3)x + C3 (1-√3)x

    now i started to find particular integral by

    Yp = 1/f(D) e^x/(1+e^(-x))
    = e^x 1/f(D+1) 1 /(1+e^(-x))
    = e^x 1/f(D+1) e^x/e^x+1

    i am stuch here... how i may go now..

    can anybody tell me how i find Particular Integral of this question?
     
  2. jcsd
  3. Mar 28, 2012 #2

    LCKurtz

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    I think your complementary solution is wrong. The roots of your characteristic equation are 0,1, and 2. Once you fix that you will need to use variation of parameters to get a particular solution of the NH equation.
     
  4. Mar 28, 2012 #3
    oh yes... thanks LCKurtz..
    but Variation of Parameters taking too long..
    do you have any other method to solve it..
     
  5. Mar 28, 2012 #4

    LCKurtz

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    Maple. :uhh:
     
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