MathGroup Archive 2001

[Date Index] [Thread Index] [Author Index]

Search the Archive

Problem with Interval Calculations?

  • To: mathgroup at
  • Subject: [mg30868] Problem with Interval Calculations?
  • From: "Greg Arnold" <garnold at>
  • Date: Fri, 21 Sep 2001 04:04:06 -0400 (EDT)
  • Sender: owner-wri-mathgroup at

Mathematica 4.1 gives me the following:

In[1]:=  expr=a*(1-a)
Out[1]= (1-a) a

In[2]:= expr /. a->Interval[{1,2}]
Out[2]= Interval[{-2,0}]

In[3]:= Expand[expr]
Out[3]= a - a^2

In[4]:= Expand[expr] /. a->Interval[{1,2}]
Out[4]= Interval[{-3,1}]

What gives?  Should the answer be the same?  I believe the expanded answer,
but I'm not sure expanding every problem before assigning the interval is

Thanks for any advice/insight,


  • Prev by Date: Exporting To Adobe Illustrator
  • Next by Date: Re: export graphics on a Suse Linux 7.0 PC
  • Previous by thread: Re: Q: Solving econometric models
  • Next by thread: Re: Problem with Interval Calculations?