Re: cannot solve *trivial* equation
- To: mathgroup at smc.vnet.net
- Subject: [mg34390] Re: cannot solve *trivial* equation
- From: Alexander Dreyer <dreyer at itwm.fhg.de>
- Date: Sat, 18 May 2002 03:50:49 -0400 (EDT)
- Organization: Fraunhofer ITWM
- References: <ac2n7c$3qr$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Marco Manfredini wrote:
>
> Hi,
>
> I just tried a friend's Mathematica 4.0.0.0:
>
> Solve[{A == S + Q, Q == 2*S}, A]
>
> => {A->3*S}
>
> Solve[{A == S + Q, Q == 2*S}, S]
>
> => {}
>
> Can somebody explain this to me? (ie. "bug","you stupid")
>
> Marco
>
Hi Marco,
this seems to be a Mathematica bug. If you give "enough" variables to
the Solve command, it is able to solve the system of equations:
In[6]:=
Solve[{A == S + Q, Q == 2*S},{Q, S}]//InputForm
Out[6]//InputForm=
{{Q -> (2*A)/3, S -> A/3}}
Alexander
--
/ Alexander Dreyer, Dipl.-Math. - Abteilung Adaptive Systeme \
/ Fraunhofer Institut fuer Techno- und Wirtschaftsmathematik (ITWM) \
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