Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Homework Helper
    Gold Member

  4. Feb 20, 2009 #3


    User Avatar
    Science Advisor
    Homework Helper

    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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook