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Dealing with Indeterminant points & ListPlot

• To: mathgroup at smc.vnet.net
• Subject: [mg2062] Dealing with Indeterminant points & ListPlot
• From: Ed Oswalt <efo at pixel.kodak.com>
• Date: Sat, 23 Sep 1995 20:34:11 -0400
• Organization: Eastman Kodak - any opinions expressed are my own...

I am using the latest Student version of Mathematica and was having a 
problem dealing with indeterminant points in in a function like
Sin[x]/x where Sin is indeterminant at x = 0 (but by L'Hopitals is
equal to 1. When I try to plot such functions Mathematica complains.

What can I do to get around this? Can I use an If[] function inside
other functions like Plot[] to test for x = 0 and sub in the value
1 for the formula in that instance? How do I do that - tried and
can't get it to work right.

I just started with Mathematica this weekend and was a little dissapointed
since my HP-48GX calculator handles these functions fine (not sure if attempts
L'Hopital's or just follows the convergance to 1). Also my prof claims matlab
handles Indeterminant points. I plan to e-mail them the suggestion to handle 
these points better (even if it means a switch to activativate finding a 
symbolic L'Hopitals solution or just following where the convergance appears
to be at.

Also I am using ListPlot[] on the same student windows version and the dots
are too small - they are invisable on the screen and barely visable on 
print out, I end up having to join the points so I can see them but that is 
not what I want to show - I want to show the points. Any Idea's on how to
make these dots "Fatter"?

Thanks for any help,

Ed Oswalt 
Part time student & Full Time Engineer
efo at dtc.kodak.com