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Homework Help: Partial fraction

  1. Feb 20, 2009 #1
    1. The problem statement, all variables and given/known data
    x^3+1 / x^2+4


    2. Relevant equations


    3. The attempt at a solution

    after using long division i get : x + -(4x-1) / (x^2+4)

    then using partial fraction :

    -4x-1 / x^2+4 = bx+c / x^2+4

    then i am stuck because if what i have
    is correct then they both are the same and in the same form.
     
  2. jcsd
  3. Feb 20, 2009 #2

    gabbagabbahey

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    [tex]-\frac{4x-1}{x^2+4}=\frac{1}{x^2+4}-\frac{4x}{x^2+4}[/tex].....:wink:
     
  4. Feb 20, 2009 #3

    Dick

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    Once you gotten to (-4x-1)/(x^2+4) you probably want to leave the partial fractions trail. Split it into -4x/(x^2+4) and -1/(x^2+4). The first one is a simple substitution. I'm going to guess the second one might be something related to arctan(x)? Try a trig substitution.
     
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