Re: Re: Problem with parametric minimization

*To*: mathgroup at smc.vnet.net*Subject*: [mg90279] Re: [mg90243] Re: [mg90186] Problem with parametric minimization*From*: DrMajorBob <drmajorbob at att.net>*Date*: Fri, 4 Jul 2008 03:58:28 -0400 (EDT)*References*: <15947055.1215088335131.JavaMail.root@m08>*Reply-to*: drmajorbob at longhorns.com

Good idea, but the result is two solutions, the second of which is incorrect: Minimize[a*x^2 + b*x + c, x] {\[Piecewise]c (b==0&&a==0)||(b==0&&a>0) ((-b^2+4 a c)/(4 a)) (b>0&&a>0)||(b<0&&a>0) -\[Infinity] True ,{x->\[Piecewise]0 (b==0&&a==0)||(b==0&&a>0) -(b/(2 a)) (b>0&&a>0)||(b<0&&a>0) Indeterminate True }} Here's Minimize failing in similar (spectacular) fashion for a LINEAR function: quadratic=a*x^2+b*x+c; linear=quadratic/.a->0 Minimize[linear,x] c+b x {\[Piecewise]c b==0 -\[Infinity] True ,{x->\[Piecewise]0 b==0 Indeterminate True }} The first solution is correct; the second is nonsense. (This is 64-bit 6.0.3 on the Mac.) Bobby On Thu, 03 Jul 2008 05:11:28 -0500, Bob Hanlon <hanlonr at cox.net> wrote: > Use multiply or space to have your expression represent what you > intended. > > Minimize[a*x^2 + b*x + c, x] > > > Bob Hanlon > > ---- Stephan Heckmueller <stephan.heckmueller at gmx.net> wrote: > > ============= > Hello, > I have a problem with with the examples for using the > Minimize function given in the documentation on wolfram.com: > > When trying: > Minimize[ax^2+bx+c,x] > > I receive the following error: > > Minimize::objv: > The objective function c+bx+ax^2 contains a nonconstant > expression c independent of variables (x). > > Is there something wrong with the command or the > documentation? > > Thanks. > > > > > -- DrMajorBob at longhorns.com

**Follow-Ups**:**Re: Re: Re: Problem with parametric minimization***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>