Texas Instruments TI-nspire

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TI-nspire

Texas Instruments TI-nspire

Type: Algebraic Electronic Calculator
Size: 4 x 8 inches / 10 x 20 cm
Serial/Lot number: 2016078547 / S-0507
Date of Manufacture: May 2007

With getting started book, hard shell case and CDROM containing soft copies of the full manual and references, and basic communications software. Also includes a second keyboard for the TI-84 Plus operating mode, with vinyl case.

The thing that caught my eye on this unit was its sheer size. Three of them side to side would scare my 12-inch Powerbook. And at nearly 10 ounces (300g), a math student toting one of these should have little to fear in dark alleys. Also in the size department is the enormous video display, 320x240 pixels at about 100 pixels per inch. This is bigger than any calculator I've yet seen and puts a few PDAs to shame. In fact, Texas Instruments would like to have us believe that the unit is a PDA. The manual refers to it as a "handheld".

The nspire is first and foremost an educational tool. Every task is organized into documents, each document holds one or more "problems" and each problem can consist of up to 50 screen images called "pages". Each page in turn can be laid out into up to four windows. The windows are where the work finally manages to get done. Even if all you want to do is add two and two, you'll have one document with one problem with one page with one window. This does take a little getting used to, but I can see the benefits even for professional users. Instead of "documents" and "problems" one can think of them as "projects" and "tasks".

The device has 32 MB of SDRAM in the main unit. The keyboard has a comparable amount of flash ram. The flash ram obviates the need for a memory backup while using the SDRAM as main store ensures speedy response. The document-based subsystem encourages you to save your work, which action copies your work to flash. One interesting advantage of this system is that you could have different keyboards holding different contents and even different operating systems. The nspire's package came bundled with a second keyboard that makes the device act as a TI-84 Plus. This is not merely an emulation. Installing the keyboard copies the TI-84 operating system and any saved items to the main SDRAM. Reinstalling the native nspire keyboard copies the nspire OS and stored documents to the main store. A mirror of SDRAM seems to be made to flash at power off since even unsaved work and previous displays appear after each change.

The two operating systems are so different that they return different values to Mike Sebastian's calculator forensics evaluation algorithm, arcsin (arccos (arctan (tan (cos (sin (9) ) ) ) ) ). The native nspire OS returns 8.9999999817691 while the TI-84 keyboard returns 8.9999999695957, consistent with the original TI-84 Plus.

The nspire OS provides 5 main applications, each of which require a window on a page in which to run. Perhaps surprisingly, one of these applications is the calculator application. (The nspire isn't so much a calculator as a general purpose computer. You have a calculator application on your desktop machine so it's not really surprising that the nspire has moved calculation to an application. Except that it is.) The calculator app gives roughly the same functionality as a TI-89 or TI-92. This unit does not support a computer algebra system (although TI does have a variant unit that does have CAS; It isn't able to act like a TI-84.)

There is a graphing application that will draw several curves on one set of axes. It will do this in a rectilinear mode, as parametric equations or as a scatter plot. A straight polar r=f(θ) plot would be a good addition, but the parametric form can serve.

There is a spreadsheet application. This can hold data typed in by hand, or retrieved from a short list of external collectors. There is a limited ability to use other cells in formulas. This is apparently on a column-by-column basis. Quite a number of statistical tests are available when you need numeric results. The application includes a "quick graph" feature allowing you to toss up a quick histogram or scatter plot.

A simple text editor is intended to help the student take notes in class. These notes can be downloaded onto the instructor's PC for feedback which would be loaded back on the unit at a later time. The nspire keyboard isn't the quickest thing to type on, so don't toss that paper and pencil yet.

Last is a statistical analyzer. This is used in conjunction with the spreadsheet application to graph data and perform graphical regression analysis. It is also used by the "quick graph" feature of the spreadsheet.

The keyboard is pretty rococo. The alphabetic keys stand about 2mm higher than the numeric and function keys. You have to get used to dodging them if you're banging in a lot of numeric data. I suppose smaller and taller puts them on an equal footing as shorter but wider.