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Math Help - ODE problem

  1. #1
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    ODE problem

    Hi.

    I have this problem:
    Use the method of undetermined coefficients to find one solution of
    y'' + 2y' - 7y = [(-1t^2)+4t+7]e^(2t).
    Find a specific solution, not a general one.

    I'm having lots of trouble finding the coefficients.
    I'm assuming I need to use [(At^2)+Bt+C]*e^(2t).
    This however does not seem to work. Can anyone confirm this as the function I need to use for differentiation?

    Thank you.
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by PvtBillPilgrim View Post
    Hi.

    I have this problem:
    Use the method of undetermined coefficients to find one solution of
    y'' + 2y' - 7y = [(-1t^2)+4t+7]e^(2t).
    Find a specific solution, not a general one.

    I'm having lots of trouble finding the coefficients.
    I'm assuming I need to use [(At^2)+Bt+C]*e^(2t).
    This however does not seem to work. Can anyone confirm this as the function I need to use for differentiation?

    Thank you.
    It works for me. I get
    A = -1
    B = 16
    C = -87

    -Dan
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  3. #3
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    Nov 2006
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    Series Solution

    Thank you for the help.
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