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Homework Help: A different DE question

  1. Dec 13, 2005 #1
    hello everybody,
    i have a different DE question, actually i have searced it in the net but didn't find the answer.
    what if there is a DE with variable coefficients (needed power series sol'n)
    but a NONHOMOGENEOUS one??? (actually it's kinda urgent, have only one day)
    for example: x^2 y'' + xy' + (x+1)y = 1/x^2
    my sol'n:
    actually i cant think of anything, if the righthand side was 0 it could be solved by
    y=SUM( an * x^(n+r) ) then apply the well known solution (the long one, cant be writen here, it is very long)
    but i dont know even which method to apply to solve a nonhomo
    by the way if the general solution i need is y = yc + yp
    yc: y complementary
    yp: y particular
    i need yp (don't know which method to use)
     
    Last edited: Dec 13, 2005
  2. jcsd
  3. Dec 14, 2005 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Write the righthand side as x-2 and fit it into your series!

    Or, if you don't like that negative power, multiply the entire equation by x^2 and write it as x^4 y"+ x^3y'+ x^2(x+1)y= 1. Include the 1 in your series for y.
     
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