Re: Solve...or not

*To*: mathgroup at smc.vnet.net*Subject*: [mg128546] Re: Solve...or not*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Fri, 2 Nov 2012 00:45:06 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <20121101072008.AE953687B@smc.vnet.net>

$Version "8.0 for Mac OS X x86 (64-bit) (October 5, 2011)" eqns = {(y - 2)/(x - 1) == 1, y == 0}; Solve[eqns, {x, y}] {{x -> -1, y -> 0}} Solve[eqns, Variables[eqns]] {{x -> -1, y -> 0}} Simplify[Solve[eqns[[1]], x], eqns[[2]]] {{x -> -1}} Simplify[Solve[#[[1]], x], #[[2]]] &@eqns {{x -> -1}} Solve[eqns, x, Integers] {{x -> ConditionalExpression[-1, y == 0]}} Reduce[eqns, {x, y}] // ToRules {x -> -1, y -> 0} Reduce[eqns, x] // ToRules {y -> 0, x -> -1} Eliminate[eqns, y] // ToRules {x -> -1} Bob Hanlon On Thu, Nov 1, 2012 at 3:20 AM, Harker, Anthony <a.harker at ucl.ac.uk> wrote: > > I've seen some discussion of Version 8's Solve[] in this group, but have I missed something explaining this? > > I have the following behaviour (both under Windows 7) > > > Mathematica 8.0.1.0 > > Solve[{(y-2)/(x-1)==1,y==0},x] > {} > > Mathematica 7.0.1.0 > Solve[{(y-2)/(x-1)==1,y==0},x] > {{x->-1}} > > Tony > > Tony Harker > Department of Physics and Astronomy > University College London > Gower Street > London > WC1E 6BT > > Tel: (within UK) 020 7679 3404 > (overseas ) +44 20 7679 3404 > E: a.harker at ucl.ac.uk > > [...] clay possesses one considerable advantage: it is resistant to fire, water, and magnetic disturbances. In [...] a few thousand years, our photographs, books and hard disks will no doubt have disappeared, but our collections of cuneiform tablets will still be there. > > Dominique Charpin, Reading and Writing in Babylon (2010) translated by Jane Marie Todd.

**References**:**Solve...or not***From:*"Harker, Anthony" <a.harker@ucl.ac.uk>