I'm a longtime TI user: I had a TI-83+ in high school, then moved up to a TI-86, which I then used in college. After college, these both got occasional use for a few years until I decided to change careers, and returned to school to study engineering. Then I pulled out the 86, which worked for about a year. (Since I had bought it used originally, it was probably 8-10 years old at this point and had undergone some pretty heavy use.)

Needing to upgrade, I polled my classmates and found that the majority of them used the TI-89 Titanium, and were very happy with it. A few people used the HP calculators with the QWERTY keyboards, but since I'd gotten used to the TI interface I figured I'd stick with it. Plus, the huge HP seemed like a bit of overkill.

Shopping experience

I bought this calculator in October 2006, and I must have had my mind elsewhere at the time because I didn't shop very well. I used froogle to find the lowest price (I think it was about $115), then ordered from what seemed like a reputable store. It was usermart.com, which - surprise! - no longer exists. They sent me the wrong calculator and it was a huge pain to get a refund. (Had I but known about epinions then . . .). For some reason I then doubled down and took the risk of buying on on eBay. I paid $84.02, for the calculator with all the original packaging, software, and USB cord. At least on eBay I had the option of checking the seller's feedback, reading about why she was selling it, etc. Fortunately, it worked out perfectly, and I've been using this calculator ever since.

If you want to avoid all risk, I'd recommend buying from Amazon, since they have a very generous return policy, plus free return shipping. They'll also do price adjustments if they offer a lower price within 30 days. But if you're feeling lucky you could try Amazon marketplace or eBay and get it for around $90. As of 6/15/08, Amazon has it for $144, which has been about the going price for over a year.

Related to the price stability: one thing I love, love, love about Texas Instruments is that they don't issue new calculators every six months. Unlike your laptop, your calculator won't be obsolete within a year.

The Basics

As I mentioned, the calculator comes with a software CD, a USB cord, and of course a manual and a case. It measures about 7 x 3 x 0.75 inches. It weighs 11 ounces, which won't break your back, but is a bit of a shock when you see how small and light things like cell phones have gotten. For comparison, the TI-86 weighs 8.75 ounces, and the TI-83+ weighs 9.5 ounces. All those weights are with batteries in and covers on.

According to the Texas Instruments website, this calculator is permitted on the AP Calculus, AP Statistics, AP Physics, AP Chemistry, PSAT/NMSQT, SAT I , SAT II, and Math IC & IIC exams.

This calculator takes four AAA batteries. The battery life on mine has been very good; I don't think I had to change the batteries at all this term.

Getting Started

The TI-89 Titanium has a pretty big users manual, but don't get too freaked out -- you can learn a lot of it as you go. To make it easier, the second section of the manual is called "previews" and gets you started on all the different functions. You can then go to the more detailed sections if you need them.

The funny thing about starting with this calculator was that it actually took me a while to get the hang of it. The transition from the 83 to the 86 was simple, but things are just different enough on the 89 to throw you off. I don't want to give the impression that the calculator is confusing: it's not. If it's your first time using a graphing calculator, there's going to be a bit of a learning curve no matter which one you choose.

Settings

You can set features of the calculator to default to certain modes, say, angles in radians and fractions instead of decimals. The problem is it's a bit of a pain to switch back and forth. One nice feature that took me a while to discover was the different folders. With these, you can set up different settings to apply at different times. So I can have a "surveying" folder that defaults to degrees, and gives me answers to the sixth decimal place, but then when I start my structural homework I can switch folders and get my answers in radians, and in fractions instead of decimals. This is much easier than changing individual settings all the time.

As I alluded to above, you can set the calculator to give you either "exact" (fractional) or "approximate" (decimal) answers. In general I prefer fractions, but they get to be a problem if you're using certain features a lot. The natural log feature, in particular, is silly: if you have the calculator in "exact" mode and you type in LN(5), the solution it gives you is LN(5). Not helpful. Fortunately, there's a built-in function for getting the approximation of this (I believe you have to hit "shift" then "enter"). But there's a problem with this: if you have say, 1/8 and you then multiply it by 3, you get 3/8. Okay, say you then want that in decimal form. When you hit "shift" "enter" the calculator doesn't approximate 3/8, it multiplies 3/8 by 3 again and then approximates it. There's a way around this, but it would be nice if the exact and approximate functions were more intuitive to begin with.

Computations

I have yet to run into something this calculator can't do, so I'll hit the things that stood out for me.

The numeric solver is a particularly nice feature compared with the other TI models I've used. Before, if I had a certain equation I used a lot, I'd write a little program to prompt me for some variables and solve for the final one. The problem is that I've never done much programming, so I never knew how to get the calculator to solve for any variable, given all the others. The 89's numeric solver function does that. Just type in your equation, put in the variables you know, and it solves for the final one. You can easily name and save these equations for future use.

There's also a separate "solve" function in the main calculation area that will solve equations for you. It can do simultaneous equations and even solve implicitly. This calculator will also do derivatives and integrals, and probably a dozen algebraic operations (zeros, etc.). Be careful using these too much, since your algebra skills will deteriorate. In fact, if I were a high school or introductory college math teacher, I don't think I would allow this calculator.

Graphing and Tables

The TI-89 Titanium can do 3-D graphing, which is really impressive. It came in handy for vector calculus, when I had trouble visualizing some 3-D functions. This type of graphing is very slow, however, so if you're going to do a lot of it you'll want to just stick with computer software like Maple or something.

There's also a Data/Matrix editor, which is sort of a mini spreadsheet program. I tried using this a couple of times, but it's a bit clumsy, so I just stuck with Excel. It could come in handy if you're not going to have access to a computer, though.

Programs

This calculator comes pre-loaded with some applications, like NoteFolio (for storing text notes) and a finance application (for things like time value of money).

Because of the USB connectivity, it's easy to get programs onto the TI-89 Titanium. Right now my calculator has a periodic table that you can scroll through to view element properties, and a program for finding friction in pipe flow (it's an iterative calculation, so it's nice to have it programmed in). You can also make digital study cards.

There are a lot of programs available in addition to the official ones from Texas Instruments. To get an idea of what's out there, look at this list of programs:

http://www.ticalc.org/pub/89/basic/programs/

That's not even 10% of what's available. Of course, the programs are of variable quality, but I've found them to be generally good. (If you want to start at the top and see all the TI-89 programs available, go to http://www.ticalc.org/pub/89/)

Conclusions

The big differences from the regular TI-89 are that the Titanium has USB connectivity and more memory. These are only really important if you're going to be running a lot of programs on your calculator.

This is a great calculator for engineering students because a lot of other students and professors use them, so help is always available. The price is comparable to other graphing calculators out there, and I think this calculator is worth it.


Recommended: Yes

Purchase Price: 84.02