Re: Intersection of sets of results

*To*: mathgroup at smc.vnet.net*Subject*: [mg37105] Re: [mg37099] Intersection of sets of results*From*: BobHanlon at aol.com*Date*: Thu, 10 Oct 2002 03:20:32 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

In a message dated 10/9/2002 6:22:03 AM, flip_alpha at safebunch.com writes: >I have two equations that I have solved for: > >x[n_] := 2331 + 8 n >y[n_] := -3108 - 11n > >I want to include only solutions which are non-negative, that is x >= 0 >and >y >= 0. > >In this example we can do 2331 + 8n > = 0 and solve for n, n >= -291.375 >and -3108 - 11 n >= 0 and solve for n, n <= -282.545 > >So we have -291.375 <= n <= -282.545. > >The "integer solution set here is for n = >{-290, -289, -288, -287, -286, -285, -284, -283}. > >So in this case we have 8 non-negative solutions. > >Given that I can supply x[n] and y[n], how do I go about finding the set >n? > Needs["Algebra`InequalitySolve`"]; x[n_] := 2331 + 8n; y[n_] := -3108 - 11n; rng = InequalitySolve[{x[n] >= 0, y[n] >= 0}, n]; soln = Range[Ceiling[rng[[1]]], rng[[-1]]] {-291, -290, -289, -288, -287, -286, -285, -284, -283} Length[soln] 9 Bob Hanlon