Re: Simplification with constraints

*To*: mathgroup at smc.vnet.net*Subject*: [mg72065] Re: Simplification with constraints*From*: "dimitris" <dimmechan at yahoo.com>*Date*: Sun, 10 Dec 2006 04:49:25 -0500 (EST)*References*: <ele6rc$rm9$1@smc.vnet.net>

Something like? Reduce[f == b*b + c*c + d*d && a*a + b*b + c*c + d*d == 1, {f, b}][[1]] f == 1 - a^2 Dimitris Vladimir wrote: > Suppose we have a constraint: > > a*a+b*b+c*c+d*d==1 > > What is the most elegant and general way to simplify any expression > considering above constraint for simplification? > > For (just a simple) example: > > In[]:=simplify[b*b+c*c+d*d] > > should give: > > Out[]=1-a*a > > -- > thanks in advance, > Vladimir