Re: Strange Behaviour of Solve?
- To: mathgroup at smc.vnet.net
- Subject: [mg79019] Re: [mg79007] Strange Behaviour of Solve?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 16 Jul 2007 02:11:20 -0400 (EDT)
- Reply-to: hanlonr at cox.net
Solve[{b == g, a == (g*v/c), (b)^2 + (a)^2 == 1}, g, {a, b}]
{{g -> -(c/Sqrt[c^2 + v^2])},
{g -> c/Sqrt[c^2 + v^2]}}
Bob Hanlon
---- Andreas Maier <andimai at web.de> wrote:
> Hi,
>
> i tried (using Mathematica 6.0) to solve a system of equations:
>
> In:=Solve[{b == g, a == (g*v/c), (b)^2 + (a)^2 == 1}, g]
> Out:={}
>
> But when i use
>
> In:=Solve[{b == g, a == (g*v/c), (b)^2 + (a)^2 == 1}, {a, b, g}]
> Out={{g -> -c/Sqrt[c^2 + v^2], b -> -c/Sqrt[c^2 + v^2],
> a -> -v/Sqrt[c^2 + v^2]}, {g -> c/Sqrt[c^2 + v^2],
> b -> c/Sqrt[c^2 + v^2], a -> v/Sqrt[c^2 + v^2]}}
>
> i suddenly get the solution for g. It seems to me, that the number
> of solutions for one variable depends on the number of variables
> i want to solve for. Is this behaviour of Solve to be
> expected?
>
> Andreas Maier
>
>