Partial fraction decomposition

In summary: There are many easier ways than this method...Check your math...you've got mistakes in there...There are many easier ways than this method...I am just checking where the mistake is, should l expand everything and then equate the coefficients ?What is the point of this conversation?In summary, the conversation was about finding the partial fraction decomposition of a given equation. The person asking the question was struggling with solving for the coefficients and was seeking guidance on how to proceed. The expert advised them to check their math and mentioned that there are easier methods to solve for the coefficients.
  • #36
Nyasha said:
For H l got [tex]\frac{-1}{4}[/tex] but for some reason l can't find G=0

[tex]x^2=A(1+x)(1-x)^2(1+x^2)^2+B(1-x)^2(1+x^2)^2+C(1-x)(1+x^2)^2(1+x)^2+D(1+x^2)^2(1+x)^2[/tex]
[tex]+(Ex+F)(1+x)^2 (1+x^2)(1-x)^2+(Gx+H) (1-x)^2(1+x)^2[/tex]


[tex]x^2=A(x^7-x^6+x^5-x^4-x^3+x^2-x+1)+B(x^6-x^5+3x^4-4x^3+3x^2-2x+1)+[/tex][tex]C(-x^7-x^6-x^5-x^4+x^3+x^2+x+1)+ D(x^6+2x^5+3x^4+4x^3+3x^2+2x+1)[/tex][tex]+(Ex+F)(x^8-3x^4+x^2+1)+(Gx+H)(x^4-2x^2+1)[/tex]

[tex]x^5\rightarrow 0=A-B-C+2D-3E+G \rightarrow 0=\frac{1}{16}-\frac{1}{16}-\frac{1}{16}+\frac{1}{8}+G[/tex]

[tex]\therefore G=\frac{-1}{16}[/tex]

Check your expansion of the [tex]B(1-x)^2(1+x^2)^2[/tex] term
 
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  • #37
gabbagabbahey said:
Check your expansion of the [tex]B(1-x)^2(1+x^2)^2[/tex] term

Thanks l got G=0. I have now solved. I don't have access to Mathematica at the university library or home. How can you get it ?
 
  • #38
You can purchase a license off their website and download it to your computer, but it is fairly expensive (~$300 for a single home use license)...most University physics and math departments have several licenses for student use, so you should ask around your department before spending money you don't have to.
 
  • #39
gabbagabbahey said:
You can purchase a license off their website and download it to your computer, but it is fairly expensive (~$300 for a single home use license)...most University physics and math departments have several licenses for student use, so you should ask around your department before spending money you don't have to.

Thanks very much
 
  • #40
There is a also a very capable free alternative to Mathematica called Maxima. http://maxima.sourceforge.net/ If you can get that installed then just type:
partfrac(x^2/(1-x^4)^2,x);
 

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