MathGroup Archive 2002

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: cannot solve *trivial* equation

  • To: mathgroup at smc.vnet.net
  • Subject: [mg34395] Re: cannot solve *trivial* equation
  • From: "milkcart" <milkcart at m17.alpha-net.ne.jp>
  • Date: Sat, 18 May 2002 03:50:56 -0400 (EDT)
  • References: <200205171031.GAA03799@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi marco

Your system of equations consists of two equations with three variables.

If a number is asigned to q, you can solve these equations with a and s.
If  a number is assigned to a, you can solve these with q and s.
Ways of solving equations are not unique. 

You can solve system of equations as follows:

In[8]:=
Solve[{a == s + q, q == 2 s}, s, {q}]

Out[8]=
       a
{{s -> -}}
       3

In[9]:=
Solve[{a == s + q, q == 2 s}, 
 
  s, {a}]

Out[9]=
       q
{{s -> -}}
       2

******************
milkcart
milkcart at m17.alpha-net.ne.jp
****************************


> 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
>  
> 
> 
> 



  • Prev by Date: Re: cannot solve *trivial* equation
  • Next by Date: Re: cannot solve *trivial* equation
  • Previous by thread: cannot solve *trivial* equation
  • Next by thread: Re: cannot solve *trivial* equation