Re: Shortening Polynomials

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg422] Re: [mg413] Shortening Polynomials*From*: danl (Daniel Lichtblau)*Date*: Tue, 24 Jan 1995 11:04:17 -0600

>...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? >.... You can do this by Normal[Series[t1, {q,0,2}]] If desired, Series/Normal will handle more variables. Daniel Lichtblau, WRI