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Homework Help: Second order differential equations

  1. May 14, 2012 #1
    1. The problem statement, all variables and given/known data

    finding the general solution. I would like to know if the 20-e^x will be treated as a sum of a polynomial?

    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. May 14, 2012 #2

    Mark44

    Staff: Mentor

    20 - ex is not a polynomial. A search on wikipedia will turn up the definition of a polynomial.
     
  4. May 14, 2012 #3

    HallsofIvy

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    It is, of course, the sum of two functions. Did you really mean to say "polynomial"?

    You should look for a "particular solution" of the form A+ Bex.
     
  5. May 14, 2012 #4

    LCKurtz

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    Gold Member

    That's a typo, Halls meant ##A+Be^{2x}##.
     
  6. May 15, 2012 #5
    can anyone help with solving it :(
     
  7. May 15, 2012 #6

    LCKurtz

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    What are you stuck on? Have you solved the associated homogeneous equation for its general solution ##y_c##? Have you tried looking for a particular solution of the NH equation of the form ##y_p=A + Be^{2x}## as has been suggested? It is all straightforward. Show us what you have so far.
     
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