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How do int. 1/(4-11x^2)^2 ?

  1. Feb 29, 2004 #1
    How do integrate 1/(4-11x^2)^2 ?

    It looks like partial fractions, but how do I do it when there is (a+bx^2)^2?

    I know it is something like

    1/(4-11x^2)^2 = Ax + b / (4-11x^2)^2
  2. jcsd
  3. Feb 29, 2004 #2


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    Then, as is often the case with posts like this, you know incorrectly. 1 over a polynomial is NOT "Ax+ anything"!
    Do you know that 4- 11x2= (2-√(11)x)(2+√(11)x) (sum and difference)? So that (4-11x2)2= (2+√(11)x)2(2-√(11)x)2?

    I would suggest something like
    [tex]\frac{1}{(4-11x^2)^2}= \frac{A}{2-\sqrt{11}x}+ \frac{B}{(2-\sqrt{11}x)^2}+ \frac{C}{2+\sqrt{11}x}+ \frac{D}{(2+\sqrt{11}x)^2}[/tex]
    Last edited: Mar 2, 2004
  4. Mar 7, 2004 #3
    Thanks! Talk about something being really broken down! :)
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