Re: collecting certain powers

*To*: mathgroup at smc.vnet.net*Subject*: [mg97605] Re: collecting certain powers*From*: Barış Erbaş <erbas.baris at gmail.com>*Date*: Tue, 17 Mar 2009 04:56:13 -0500 (EST)*References*: <e9fca870903160410x2b1c7c02x87c23d4dbab2de99@mail.gmail.com>

Dear Mathematica users, I have a problem which may be straightforward, but I was unable to find an answer. The problem is this: I have an expression which contain many terms with variables, t, \tau and 1/\lambda. I need to Collect all terms in powers of 1/\lambda, which I did. However, in the result I want the constant term to disappear, i.e. after applying the command (either Collect, or a more suitable one) I only want terms in powers of 1/\lambda. Collect does not give me want I want. Also, is it possible to order the obtained expression in terms of increasing (or decreasing) powers of the variable. Mathematica seems to be ordering a little randomly. Many Thanks, Baris.