Re: Problem finding maximum

*To*: mathgroup at smc.vnet.net*Subject*: [mg127602] Re: Problem finding maximum*From*: Cisco Lane <travlorf at yahoo.com>*Date*: Mon, 6 Aug 2012 04:37:48 -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

Hmm - My Mathematica (Mathematica 7 Home Edition, Ver 7.0.1.0, Mac OS X X86 (32-bit)) gives a different answer: f[x_, a_] = (a^3 - 6 x - a^2 (4 + x) + a (2 + 12 x - 4 x^2))/(8 a); aa1 = .7481; NMaximize[{Abs[f[x, aa1]], 0 <= x <= aa1}, x] {0.0274936, {x -> 0.403948}} Any idea why? I must use an automatically selected start point, because the values of aa1 vary widely. Using the rational aa1 and Maximize works: f[x_, a_] = (a^3 - 6 x - a^2 (4 + x) + a (2 + 12 x - 4 x^2))/(8 a); aa1 = 7481/10000; N[Maximize[{Abs[f[x, aa1]], 0 <= x <= aa1}, x]] {0.0540933, {x -> 0.}} but I am not sure why. If this method is reliable, I could use it, but it seems klugy.

**Follow-Ups**:**Re: Problem finding maximum***From:*Bob Hanlon <hanlonr357@gmail.com>