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Homework Help: Particular Sol to ODE

  1. Sep 12, 2011 #1
    Find a particular solution for the following non-homogeneous di eren-
    tial equation by the method of undetermined coefficients:

    a. y'' + 8y' +12y = e^-2x + sin(2x)

    b. y'' + 11y' - 12y = 3x^2 + 4 + e^x

    I got for a. Yp(x) = 1/4xe^-2x + 1/40cos(2x) +1/20 sin(2x)

    b. Yp(x) = -1/4x^2 - 11/24x - 229/288 - 1/13xe^-x

    I have a feeling that a is right but not sure about b.
  2. jcsd
  3. Sep 12, 2011 #2


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    Science Advisor
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    Gold Member

    Plug them back into the NH equation and see if they work. Then you will be sure.
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