Re: Shortening Polynomials
- To: mathgroup at christensen.cybernetics.net
- Subject: [mg417] Re: [mg413] Shortening Polynomials
- From: Richard Mercer <richard at seuss.math.wright.edu>
- Date: Mon, 23 Jan 1995 08:48:41 -0500
> Dear Mathgroupers,
>
> Many thanks for all the replies I got for my previous
> requests. I have a feeling this may be trivial, but I
> often want to shorten polynomials, after using Expand.
> At the moment, I use the following type of unwieldy
> expression:
>
> t1 = a0 + a1 q + a2 q^2 ;
> Expand[%^4] /.
> {q^3->0,q^4->0,q^5->0,q^6->0,q^7->0,q^8->0};
>
> Is there a neater way to collect powers up to order m
> after expanding a polynomial?
>
> Thanks, Stephen
Take[Expand[t1^4],3] is what you want.
Richard Mercer