Robert Jantzen

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16 years, 180 days

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I started using Maple in undergraduate mathematics teaching in 1994 and eventually in my research in general relativity. I maintain a huge publicly accessible (permits directory listing of folders) archive of maple worksheets, most of which I generated along the way in my enthusiasm for Maple, but which hardly anyone uses, including myself. Here is how I try to keep my institution up to date: My research connections are here:

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These are replies submitted by Robert Jantzen

@Carl Love As I said above, things change and there is an increasing tendency to hide menus and scroll bars and links etc from view. In this case I had not seen the up arrow upload icon before. But I am willing to learn! :-)

@Carl Love I haven't done this in a while, so things change. I never saw any way to attach a file to this post, and absentmindedly submitted it with no attachment. What did I miss?

Well, I also forgot to check the box to receive replies to this comment! Great. Now that I am editing it, I don't see the check box.



Wow, these responses have been really useful. I will be studying the various solutions. Thanks to each of you for your prompt responses.

Thanks! I tried putting right quotes around various parts of the expression, but obviously failed since I was blindly editing without any clear idea of what would work. This delayed evaluation problem should be addressed by Maplesoft in some Help page because it is not clear to nonexperts when it is necessary and how it works. Creating animations seems like an activity that elementary users should be able to do without being derailed with no online resource to consult.

This morning I had 20 minutes before leaving for a class that I wanted to show a derivation of the equation of a tangent plane at a generic point in order to derive a property of the tangent plane as  a function of position, and the dreaded overbar came into my formula from the palette dot product, so finally after years of not trying to find a work around I called tech support since I was out of time and was informed that by using either Student[LinearAlgebra] or VectorCalculus, this would not occur since it assumes variables are real! I had only loaded LinearAlgebra, and I had always thought Student just had the extra tutorials and a few less commands like the elementary row operation commands compared to the full package, but NO. Finally I learned the simple answer. I should have known Robert would have the answer. Thanks, Robert.

I am sitting here by myself after 6pm during a transit strike in Rome, already abandoned by my colleagues in this applied math research institute, and the Maple newsletter entry captured my immediate attention. Robert, you are inspiring. Please keep these gems coming. Meanwhile I will eat more pasta tonight...(but gastritis is reducing my allowed wine intake!  :-( )

I better get moving or I will miss my window of opportunity when the strike takes a rest during evening rush hour...I still don't understand how these strikes work. Pardon my comment devoid of mathematics, but we are also living our lives while doing mathematics...

I cannot resist adding another comment. If you had animated this graph but going inside the original parabola instead of outside, you would have seen the normals forming a caustic curve: the evolute of the parabola. I have a way too long worksheet on various properties of the evolutes of the ellipse, and one of the last things I did was make animations of these curves which are a fixed distance along the normal lines, which develop singularities along the evolute. Very cute and so reachable from elementary calculus with a tool like Maple. 
This is sort of like optics but in physical optics you have to recalculate the new normal at each successive curve to get the wavefronts, not continue along the original normals. But still it gives a flavor of what happens in optics.

As a physicist in a math department, I think being able to write an equation for the tangent line at an arbitrary point on a curve, and then place a condition on it to solve some interesting problem, is a perfect example of what calculus is all about, and of course Maple is the perfect tool to do this. Your example here is really inspiring.

But I am only one person in a big department very aware that my colleagues and even our textbook whose author built a 24 million dollar house from his profits will not support me in being different from the norm, so I have wimped out.

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