       Re: just doesn't work

• To: mathgroup at smc.vnet.net
• Subject: [mg25393] Re: just doesn't work
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Fri, 29 Sep 2000 01:06:26 -0400 (EDT)
• Organization: Universitaet Leipzig
• References: <8qho5p\$j9s@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

a) Mathematica is a Computer Algebra -- *not* a text editor, vi is
a text editor and emacs
b)

expr = (4 a^3 b c K Pi Ro)/(15 r^3)

expr /. First[Solve[(4 a b c Pi Ro)/3 == m, Ro]]
c)

In[]:=MyFactor[expr_, q_] := q*Simplify[expr/q]

In[]:=MyFactor[a^2 b c + a b c, a b c]
Out[]= a (1 + a) b c

Regards
Jens

Borut L wrote:
>
> Helo,
>
> I am writing a paper in Mathematica 4.0, and I found it to be very powerful
> text editor. However, I encountered some deadly problems, which I cannot
> solve. Thanks for any help!
>
> 1. How can I replace a symbol m with (4 a b c Pi Ro)/3 in expr
>
> (4 a^3 b c K Pi Ro)/(15 r^3)
>
> expr/.(4 a b c Pi Ro)/3 -> m
> just doesn't work
>
> 2. How Can I 'bring out' a defined part from a sum of two terms.
>
> ] - (would produce) - > a b c (a+1)
>
> Collect[expr,{a,b,c}]
> just doesn't work.
>
> Borut, f.r.o.m. Slovenia

```

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