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