Decomposition of rationnal fractions



On 5/13/10 2:48 PM, Nicolas FRANCOIS wrote:
> Hi.
>
> Is there any way to obtain the decomposition in simple elements (don't
> know exactly how to say this in english) of a fraction of the form :
>
>           1
>   -------------------
>   (1-X)(1-X^2)(1-X^5)
>
>   
I though powerseries might give what you want, but it makes a big mess
involving %i.  It does a decent job for two terms:

powerseries(1/(1-x)/(1-x^2),x,0) ->

1/4*sum((-1)^i8 + 2*i8 + 3)*x^i8, i8,0,inf)

taylor(1/(1-x)/(1-x^2)/(1-x^5),x,0,20) gives something, but not the
general formula for the coefficients that you might want.

Ray