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Re: Mathematica question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg124793] Re: Mathematica question
  • From: Barrie Stokes <Barrie.Stokes at newcastle.edu.au>
  • Date: Tue, 7 Feb 2012 04:02:23 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201202060739.CAA10233@smc.vnet.net>

Howie

Sorry to answer like this, but Mathematica's fully cross-linked built-in Help is incredibly comprehensive and detailed.

All I'll tell you is, to find out about a function or symbol (usage, syntax, parameters, lots of examples), select the function, and hit F1 on a PC.

Or, on *any* machine, input, say "?FullSimplify" (i.e., a question mark immediately preceding the name of the function or symbol you want Help on), and the output will be some helpful text, and a blue link looking like ">>". Hitting that link will take you straight to Mathematica's built-in Help for that function or symbol.

(When you do this, you will quickly discover that "$assumptions" is not even correct Mathematica syntax - which is why it's blue, not black. Maybe you should check your source?)

If I run your code as is, I get the same output as if I'd input "expr // FullSimplify". Since expr is a list, you don't need to construct an output list as this code does. FullSimplify acts on each element in the list, and returns a list. There, I've told you more than I said I would; can't help myself.)

Given the existence of this system, I personally think it is unreasonable of you to ask "Can you explain symbol by symbol?"

I have answered in this way because, as I have more than once said in this Group,

"Give a man a fish, feed him for a day. Teach a man to fish, feed him for a lifetime".

Barrie

>>> On 06/02/2012 at 6:39 pm, in message <201202060739.CAA10233 at smc.vnet.net>,
Howie <hcohl001 at gmail.com> wrote:
> 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!




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