Re: coefficient of a polynomial term
- To: mathgroup at smc.vnet.net
- Subject: [mg59361] Re: [mg59339] coefficient of a polynomial term
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 7 Aug 2005 03:46:55 -0400 (EDT)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
poly=2 x^2+3 x*y+4 y^2+x^3
x^3 + 2*x^2 + 3*y*x + 4*y^2
Note that the output order is not the same as input order. Further, both differ
from the order in which the terms are stored
List@@poly
{2*x^2, x^3, 3*x*y, 4*y^2}
The usual way to extract coefficients is
CoefficientList[poly,{x,y}]
{{0, 0, 4}, {0, 3, 0}, {2, 0, 0}, {1, 0, 0}}
However, if you want to specify the order of the coefficients
Coefficient[poly,#]&/@{x^2,x*y,y^2,x^3}
{2,3,4,1}
Bob Hanlon
>
> From: "Tun Myint Aung" <tma at nus.edu.sg>
To: mathgroup at smc.vnet.net
> Date: 2005/08/06 Sat AM 01:29:28 EDT
> Subject: [mg59361] [mg59339] coefficient of a polynomial term
>
> Dear Mathgroup,
>
> One more question again! How to extract the coefficient of a polynomial
term. For example:
>
> poly = 2 x^2 +3 x*y +4 y^2+x^3
>
> I would like to get 2 for first term, 3 for second term, 4 for third term and
so on..
>
> Thank everyone for answering my questions
>
>
> With Regards,
>
> Tun Myint Aung
>
>