Re: A problem with Maximize/Minimize

*To*: mathgroup at smc.vnet.net*Subject*: [mg119720] Re: A problem with Maximize/Minimize*From*: Dana DeLouis <dana.del at gmail.com>*Date*: Sat, 18 Jun 2011 19:56:47 -0400 (EDT)

Wow. This is bad. Here=92s your equation, and the wrong answer: equ={30 x+20 y+15 z,7 x+7 y+3 z<=100,3 x+y+2 z<=50,x>=0,y>=0,z>=0}; Maximize[equ,{x,y,z},Integers] {490,{x->10,y->0,z->10}} Since everything is positive, I just dropped the y>=0 part. I get same solution, but also a different wrong answer. equ={30 x+20 y+15 z,7 x+7 y+3 z<=100,3 x+y+2 z<=50,x>=0,y>=0}; Maximize[equ,{x,y,z},Integers] {510,{x->10,y->0,z->10}} = = = = = = = = = = Dana DeLouis $Version "8.0 for Mac OS X x86 (64-bit) (November 6, 2010)" On Jun 17, 12:09 am, Gary Wardall <gward... at gmail.com> wrote: > A problem with Maximize/Minimize: > > Clear[x, y, z] > > Maximize[{30 x + 20 y + 15 z, x >= 0, y >= 0, z >= 0, > 7 x + 7 y + 3 z <= 100, 3 x + y + 2 z <= 50}, {x, y, z}] > > {450, {x -> 10, y -> 0, z -> 10}} > > Maximize[{30 x + 20 y + 15 z, x >= 0, y >= 0, z >= 0, > 7 x + 7 y + 3 z <= 100, 3 x + y + 2 z <= 50}, {x, y, z}, = Integers] > > {490, {x -> 10, y -> 0, z -> 10}} > > I think the problem is obvious or am I confused? I'm using Mathematica > 8 on an Apple Power Book 10.5.6 > > A similar problem exist with Minimize. > > Minimize[{-30 x - 20 y - 15 z, x >= 0, y >= 0, z >= 0, > 7 x + 7 y + 3 z <= 100, 3 x + y + 2 z <= 50}, {x, y, z}] > > {-450, {x -> 10, y -> 0, z -> 10}} > > Minimize[{-30 x - 20 y - 15 z, x >= 0, y >= 0, z >= 0, > 7 x + 7 y + 3 z <= 100, 3 x + y + 2 z <= 50}, {x, y, z}, = Integers] > > {-490, {x -> 10, y -> 0, z -> 10}} > > Gary Wardall