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Homework Help: Second order differential equation

  1. Feb 22, 2006 #1
    I just came across this one, was going really well until i came across this one.

    (d^2y/dx^2) + (dy/dx) = e^(-x)
    m^2 + m = 0
    m = -1 and m = 0

    Now i get the particular integral
    Try y = ke^(-x)
    (dy/dx) = -ke^(-k)
    (d^2y/dx^2) = ke^(-x)

    ke^(-x) - ke^(-x) = e^(-x)

    I get stuck here as k-k= 0, not one.

    Any help would be greatly appreciated.
  2. jcsd
  3. Feb 22, 2006 #2
    Try [tex]y=axe^{-x} +be^{-x}[/tex]

    Last edited: Feb 22, 2006
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