Re: Reduce::inex problem
- To: mathgroup at smc.vnet.net
- Subject: [mg114350] Re: Reduce::inex problem
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Thu, 2 Dec 2010 05:37:01 -0500 (EST)
On 1 Dec 2010, at 08:13, Eduardo Cavazos wrote:
> Hello,
>
> This seems like a pretty simple set of equations, but it's stumping
> reduce:
>
> {
> Subscript[V, b] == 4/3*Pi*Subscript[r, b]^3,
> Subscript[V, a] == 4/3*Pi*Subscript[r, a]^3,
> V == Subscript[V, b] - Subscript[V, a],
> \[Rho] == m/V
> };
> % /. {Subscript[r, b] -> 5.75,
> Subscript[r, a] -> 5.70, \[Rho] -> 8.92};
> Reduce[%]
>
> Of course, Solve can handle it. (Change the last expression to
> Solve[%,m].)
>
> Any thoughts on helping Reduce out here?
>
> Ed
>
Clearly Reduce does not like subscripts.
{Vb == (4*Pi*rb^3)/3, Va == (4*Pi*ra^3)/3,
V == Vb - Va, \[Rho] == m/V};
% /. {rb -> 5.75, ra -> 5.7, \[Rho] -> 8.92};
Reduce[%]
Vb == 796.3282878380627 && Va == 775.7346243950061 &&
V == 20.593663443056585 && m == 8.92*V
Andrzej Kozlowski