Forced Upper Case

[Luke Setzer]

Is there any way to force the product to display variable names in
upper case?

I am thinking specifically of Greek special characters.

It seems silly to be able to enter an upper case Greek letter if the
software automatically changes it to lower case.

Physics has special meanings for these characters so distinguishing
them becomes important for clarity!

[Nelson Sousa]

the case is maintained in the unit names and some system variables. On
user defined variables or units, all variable names are case
insensitive. So, I'm afraid the answer is no.

The only TI calculators that used case sensitive variable names were
TI-85 and TI-86. Case sensitivity was dropped with the TI-92 and all
subsequent models only use case insensitive variable names. It's a
pity actually, I really enjoyed the ability to distinguish between x
and X.

And yes, in Physics and Chemistry uppercase and lowercase letters can
have totally different meanings.

Nelson

[lafacroft]

Case-sensitive variable-names would be a great idea to include in the
next version of TI-s operating system for the Nspire. As a TI-86
owner, I have used case-senstive names and found them to be quite
useful.

[Daniel Dudley]

All's quiet on the Nspiring front.

I was wondering if anyone had a file that could demonstrate some 3D trig, i.e. a file that had some 3D figures that can be rotated and has some projections of an edge to another edge, etc.

Dan

________________________________

[Nelson Sousa]

I've built a few of those (3D objects, I mean): a set of polyhedra and
a set of molecules, rotated in 3D space with perspective.

You can download them here:
http://nelsonsousa.pt/index.php?lang=en&cat=2&subcat=3&article=40
http://nelsonsousa.pt/index.php?lang=en&cat=2&subcat=3&article=41

As for building other 3D objects, here's the trick: first get the 3D
coordinates of all relevant points on a spreadsheet; the projected
coordinates will be displayed as a scatter plot. Now that you have the
projected set of points you draw over it, rotating it as necessary to
understand which points represent what.

The polyhedra and molecules viewers have a spreadsheet hidden on every
page (at the right). Show the spreadsheet so that you can edit the 3D
coords on columns A, B and C, and go from there (the scatter plots, as
well as a lot of auxiliary objects, are hidden). Use the controls to
rotate the scatter plot on 3D space as needed.

But first delete all geometrical objects already drawn, as they
probably won't be needed (delete also hidden segments, points, etc.;
don't delete the scatter plot). Mind that, especially on the case of
molecules, size perspective was exagerated. If you want a realistic
perspective you should edit the relevant formulas to determine the
correct size of spheres.

You should be carefull not to over do it: anything over 10 or 12
points will have a significant performance loss, so I would advice
against it. Try to keep it simple, as the final construction will be
somewhat confusing and performance on the handheld will be very poor.

One last thing: you can draw straight edges quite easily, as the 2D
projection of a segment or line is also a segment or line. But it's
very hard to project a curve: a circle will look like an ellipse and
there's no way to do that unless defining a lot of points and
approximate that curve as a polygon. But that kills the performance.


Hope this helps!

Nelson