The TI-89 Titanium is a first-class toy!

Author's Rating:

Pros: Fast, versatile, capacious for a calculator. Presently the extreme high end of performance.

Cons: Learning curve. Teachers don't like the gaming and cheating possibilities.

The Bottom Line: 
The TI-89T is an excellent calculator for high school, college, gaming, professional and scientific use. If you need something more muscley, buy a computer.

Author's Review
I never really had a graphing calculator before, and I wanted to get a good one. Everybody who had something to say on the subject said that the TI-89 Titanium was the best in the class. So I went on eBay and bought one for $110 plus $8 shipping.

The prices have been coming down since I made my purchase on 4 September 2008, probably because students heading back-to-school have finished making their new calculator purchases, so there's less demand and fewer bidders. They're selling on eBay now for anywhere between $70 to $100. I'm still watching them in my eBay account because I might buy another TI-89T as a back up for the one I have.

I was lucky with my particular machine. It's one of the more recent ones with Hardware Version 4, which includes the faster 16 MHz Motorola CPU. The previous version of the TI-89T was HW3, which ran at 12 MHz. And on my calculator the latest operating system, OS 3.10, was already installed. If you buy one with an earlier OS, you can download 3.10 from the Texas Instruments website and then download it again from your computer to the calculator via a USB cable that comes with the calculator.

Since this is my first graphing calculator, I wasn't troubled by having to "unlearn" habits that worked on earlier or other models. Learning to use the TI-89T takes a few days, but once you do you have a calculator with more functionality than most of the home computers of the late-1980s had.

I learned TI-BASIC in about a day (it helped that I've used four other computer languages) and have written two programs, one to convert a calendar date to a Julian date, and the other to find the right ascension and declination of the sun, the planets, and the first 12 asteroids, after the user inputs a Julian date. I've also written a custom 2-dimensional arctangent function that can be called by any program that I might write on the calculator in the future.

There's a special "data" type of array variable that can handle loads of information, such as the orbital elements for those space objects, which I copied from JPL's website. And the TI-89T doesn't forget stored information when you turn it off, or even when you replace the four AAA batteries it uses for main power, because there's a backup silver oxide battery that keeps your stuff alive.

While writing my first two programs, I noticed that the user-interface is rather slow, compared to the speed at which I can type on a computer. Fortunately, TI sells a keyboard for the TI-89T calculator, which I've bought but which has not yet arrived in my mail.

Although you can upload your calculator files to your computer, and, from there, save them to the Internet or to local media, it would be nice if Texas Instruments would make a custom external storage device, such as a read/write CDROM device, that would connect directly to the TI-89T via the USB cable. That would ease the 2.7 megabyte limit for internal file storage.

I'd advise the manufacturer to avoid schemes for inserting media to the calculator itself. One reason is cleanliness: repeated insertion of media can bring dust, moisture, grease, etc., to the calculator innards, which would be a bad thing. Another reason is energy. Media readers use power, and the calculator batteries ought not to be taxed unnecessarily. The cable links were a good idea: they should be used to connect the calculator to whatever external storage device that Texas Instruments might someday make for the TI-89T.