Re: TI 85,86, HP or Casio?


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Re: TI 85,86, HP or Casio?



Raul G <"Raul G"@WORKER.COM>

>  Folks,
>     Perhaps one of you can help. I am a machinist by trade and a number
>  of my co-workers have purchased and programmed the TI 85 to suit our
>  needs (trig. functions mostly). I am shopping around for a programable
>  calculator and would appreciate any advice on the respective merits of
>  the TI 85 versus the TI 86  or if Casio or HP offer comparable
>  calculators.  Our needs run to trig. formulas, storage for threading
>  formulas, the cutting speeds of various materials, properties of oils,
>  coolants, etc.
>  I would appreciate any advice.
>  Thank You,
>  Raul G.

Why are you shopping for a new calculator? Do you want to do things that you
can't on the TI-85, or is it merely that your present calculator is wearing
out? What you might want to purchase depends pretty strongly on the answer to
this question.

Think of the TI-86 as an improved TI-85. It works very much the same as the
TI-85 (not much new learning involved) and will run the TI-85 software with
little or no problem. One of the immediately-noticeable improvements is the
clear, sharp display, which might be significant if you are using the
calculator in a demanding environment. Another significant improvement
(although it might seem small) is the _deep recall_ added -- you can call back
and re-execute not merely the most recently executed command, but the command
before that, and the command before that, and so on.  If you do any significant
amount of calculation on the home screen this can save you bundles of time.
Another added feature is the _table_ feature for looking at values of the
functions y1, y2, etc. for specified values of x. This is invaluable in using
the calculator to teach math with, but may or may not be of significant use to
you. There are, of course, quite a few other, smaller improvements over the 85.

The TI-89 is a whole new ball game, allowing for manipulation of _formulas_ and
_algebraic expressions_ in addition to just calculating numerical results.
Perhaps more significant in your situation would be simplification of
trigonometric expressions. Is this something you are interested in?
Calculating on the home screen is perhaps less convenient than on the TI-85 or
TI-86, because of the single line at the bottom of the screen which is all the
room you have for entering your command (scrolling back and forth as
necessary). Of course, you have cutting and pasting, and all that, as
well as the ability to recall combinations of previous lines. The results are
displayed on the screen above in "pretty-printed" form, which means that if you
are in exact mode you can get fractions and radicals automatically displayed.
Would this be helpful in your situation? Calculations can be significantly
shortened by using _data arrays_ (lists and matrices and other non-scalar
variables). There would be a learning curve for all this, of course. You
mentioned that you (or your colleagues) have programmed the TI-85. Compared to
the programming environment on the TI-85 the TI-89's programming capabilities
are a dream! If you wanted to put in some effort (remember that old
learning curve again) you could probably set up some really slick
programs matching your needs, and spend 90% or more of your time just
interacting with these programs (good control of input and output, where you
want it on the screen!). There is a capability on the TI-89 to work directly
with _units_ (including a way to set up your own, I believe). It's a much, much
richer environment for the user, if what you really want to do is "move up".

Perhaps someone more familiar with the general capabilities of competing
calculators (including HP models) could sum up for you their general operating
differences from the TI-85. Good luck.

RWW Taylor
National Technical Institute for the Deaf
Rochester Institute of Technology
Rochester NY 14623

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