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Texas Instruments Announces New Calculator
S. Kinney writes "TI recently announced the development of a new calculator, known as the Voyage 200, to replace the TI-92+. The software changes are rather minor, as the device is designed to be compatible with the 92, though the addition of a clock makes the Voyage more functional for some, and the case of the device enjoys a new design. Perhaps the most useful upgrade to the 92+ is the addition of more memory, for a sum of 2.7 MB of storage. No word on release date, but it'll be interesting to see how this comes out. It may be one more step towards releasing a modern-day Avigo, their failed PDA from a few years back. "
It seems they changed the connectors. That's good, but I hope the plug sticks a bit better.
I can't remember how many times my 2 players, 2 calculators chess games crashed because the cable had moved a tiny bit.
-- don't discount flying pigs until you have good air defense
While many students treat their TI calculators as toys, they are also valid tools for many others. Also, take a look at the software archives at ticalc.org. I believe an RPN input program was actually released to allow for you RPN-fans to use it.
Pax Digitalia
So get a TI-89. Looks like the rest of the boring TI series, no QWERTY keyboard, so it can be used on the SATs (I think that is the main reason TI made it). But still has the fuctions and can run the programs of the 92.
Maybe if I had an 89 in HS, I might have gone past Geometry (Algebra II was before that, had part I in middle school). Those same overworked, undermotivated teachers made me hate math so much. If I had the ability to automate away the 2 hours of homework each night, I might have stuck around to see what Trig and Calc held for me. As it was, I didn't get those until college.
Well, the major advantage of the 89/92 line over the older series is that it can do advanced Algebra and Calculus functions. Mine does derivatives, integrals(definite *and* indefinite -- very nice), series, limits, and so forth. Also, the newer ones have the capability to handle calculations involving infinity, and will also give exact answers: for example, lim x-> infinity of (1 + 1/n)^n comes out as e, which is more useful than the decimal form. The interface on the 89/92 is also improved, with a menu system supplementing the traditional pushbuttons. I wouldn't be without my 89 when doing "real" math(higher level calc, physics), but I think it's a bit overkill for the high school level.
Visit the
Texas Instruments is notorious for releasing excellent consumer electronics products and then either crippling them or letting them wither and die. Witness the Avigo and the TI99/4A.
In the case of the Avigo, it was arguably a better PDA than the Palm Pilot that it was competing against. The applications it sported were certainly better and more comprehensive than those Palm was offering. However, TI made the dev kit for the Avigo platform expensive and difficult to obtain, so nobody of consequence wrote any additional software for the Avigo.
You would think Texas Instruments would have learned their lesson after doing exactly the same thing with the TI99 home computer 15 years before. Both platforms were innovative, high quality products that became commercial failures due to poor marketing and dismal support.
I have to wonder why they even bother to develop these products. It's like consumer product development and manufacturing is a hobby for them, but marketing and support are too much of a pain in the ass, so they don't do it.
You can pick up an m100 real cheap, plenty of memory, and get some great graphing software relatively cheaply (check out powerOne graphing software for the Palm). There are also some great, free RPN calcs for the Palm, and I am sure many many more other programs than will every be available for the TI.
-josh
I've computed one of the intersection points. I'll give you the method to use since typing in all the work is a bit much for a little Slashdot box like this without access to decent math symbols :) You can use this method to compute the other 6 intersection points. Throughout I'm assuming that we're using radians for our degree measures.
t ^2 +...)))))
:)
First, we can deduce pretty quickly that all of the valid solutions lie in x [-2pi,2pi]. Draw a graph and simply plot the two lines. The cubic formula tells us that the first equation has 1 real and 2 complex roots so there aren't any intercepts other than the one near -6. If you're very good at drawing graphs you can already determine that there are 7 intersections of the two curves although the positive solutions may require steady hands.
Since we want intersections, set the ys equal to each other and simplify until we have a polynomial on one side and a trigonometric on the other.
(-0.437x^3-1.42x^2+4.84x-14.4)/13.9=sin(8.16x)
Next we use the continued fraction expansion for sin to give us the approximation
sin(t)=t/(1+t^2/(6-t^2+(6t^2/(20-t^2+20t^2/(42-
In our case do t=8.16x as a substition and we can truncate the expansion at a convenient point because it's good enough for the range -pi to pi which is essentially the range we're interested in from above.
Now, cross multiply until we have equality between two big honking polynomial expressions. Move one side over and we've got a polynomial in x equal to 0. Is this starting to look more solvable?
Take the first derivative and do a few iterations of Newton's method. You'll probably want to keep the graphs from the beginning around for your initial guesses. I did the leftmost solution since that one should have the least accuracy due to our approximation of sin. I got (-6.131,5.66) although you can of course carry these calculations out to any desired accuracies.