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## Re: [Axiom-developer] Re: partfrac, expand, combine, rewrite and simplif

**From**: |
Dylan Thurston |

**Subject**: |
Re: [Axiom-developer] Re: partfrac, expand, combine, rewrite and simplify. |

**Date**: |
Tue, 7 Oct 2003 12:24:48 -0400 |

**User-agent**: |
Mutt/1.5.4i |

On Tue, Oct 07, 2003 at 10:19:14AM -0400, Tim Daly wrote:
>* > // 2 //*
>* > I call partfrac the transform as 2x^3 / (1-x^2) = 1/(1-x) - 1/(1+x) - 2x*
>* > *
>* > What is its name in axiom ?*
>* *
>* The partialFraction function will create a partial fraction thus:*
>* *
>* -> partialFraction(7,12)*
>* *
>* 3 1*
>* 1 - -- + -*
>* 2 3*
>* 2*
>* Type: PartialFraction Integer*
Right, but this doesn't help with the actual problem! Apparently to
convince partialFraction to work on polynomials you need to provide some
type information.
Furthermore, I think there's a bug here:
------
(8) -> partialFraction((2*x^3), (1-x^2))
There are 1 exposed and 1 unexposed library operations named
partialFraction having 2 argument(s) but none was determined to
be applicable. [snippage]
(8) -> partialFraction((2*x^3)::UP(x, FRAC INT), (1-x^2))
2x
(8) - 2x - ------
2
x - 1
Type: PartialFraction UnivariatePolynomial(x,Fraction Integer)
(9) -> partialFraction((2*x^3), (1-x^2)::UP(x, FRAC INT))
1 1
(9) - 2x - ----- - -----
x - 1 x + 1
Type: PartialFraction UnivariatePolynomial(x,Fraction Integer)
------
Why didn't input (8) above actually do the partial fraction expansion?
Peace,
Dylan

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