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