Mathematica question

*To*: mathgroup at smc.vnet.net*Subject*: [mg124784] Mathematica question*From*: Howie <hcohl001 at gmail.com>*Date*: Mon, 6 Feb 2012 02:39:11 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Let's say you've got an expression expr = {Sin[x] + x^2 - x^2*Cos[x], x^3 (1 + x^2) - x^3, x^4 - x^3} What does this mean? Table[expr[[j]] // FullSimplify[#, $assumptions] & /@ # & // Expand // @ # &, {j, 3}] I am new to Mathematica as far as these more complicated expressions are concerned. Can you explain symbol by symbol? I realize that the [[j]] is Part and that FullSimplify is applied // Postfix to expr, but I don't understand what $assumptions means (I'm assuming that these are some assumptions added to FullSimplify) but I do not know where these assumptions come from. Are these assumptions the rest of the stuff on the right-hand side? In reality I have a potentially much more complicated form of the expr. Thanks!

**Follow-Ups**:**Re: Mathematica question***From:*DrMajorBob <btreat1@austin.rr.com>

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**Re: Mathematica question***From:*Barrie Stokes <Barrie.Stokes@newcastle.edu.au>

**Re: Mathematica question***From:*Murray Eisenberg <murray@math.umass.edu>