View Full Version : How do int. 1/(4-11x^2)^2 ?
Matt Jacques
Feb29-04, 02:46 PM
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
HallsofIvy
Feb29-04, 06:31 PM
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
\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}
Matt Jacques
Mar7-04, 08:26 AM
Thanks! Talk about something being really broken down! :)
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