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