Re: differences in Solve with -1/2 and -0.5Re:

*To*: mathgroup at smc.vnet.net*Subject*: [mg44401] Re: [mg44386] differences in Solve with -1/2 and -0.5Re:*From*: "Kenneth Levasseur" <Kenneth_Levasseur at uml.edu>*Date*: Sat, 8 Nov 2003 04:50:46 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

I'm using V4.2 on a Mac right now and I'm away from my office, so I can't check my V5. At least one of my students who is using Mathematica for Students - V5, got the same "division by zero" message. KL ----- Original Message ----- From: Andrzej Kozlowski <akoz at mimuw.edu.pl> To: mathgroup at smc.vnet.net Subject: [mg44401] Re: [mg44386] differences in Solve with -1/2 and -0.5 > On 7 Nov 2003, at 19:16, Kenneth Levasseur wrote: > > > Can anyone give a good reason why there is a difference in the > > following? Preferably one that my students will understand. > > > > In[1]:= > > Solve[D[x E^(-x/2), x] == 0, x] > > Out[1]= > > {{x -> 2}} > > In[2]:= > > Solve[D[x E^(-0.5*x), x] == 0, x] > > General::dbyz:Division by zero. > > Out[2]= > > {} > > > > Ken Levasseur > > Math. Sciences > > UMass Lowell > > > > > > > > What version of Mathematica? In 5.0 I get: > > In[4]:= > Solve[D[x E^(-x/2), x] == 0, x] > > Out[4]= > {{x->2}} > > In[5]:= > Solve[D[x E^(-0.5*x), x] == 0, x] > > Out[5]= > {{x->2.}} > > > > > Andrzej Kozlowski > Yokohama, Japan > http://www.mimuw.edu.pl/~akoz/ > > > > E1-I: This message has been scanned for viruses and dangerous > content by UML's antivirus scanning services. > > > >