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Really. I've played with it for a while now, and it's junk. Why couldn't they at least require a 35 or something I wouldn't mind owning. A 50 would be nice, and surely I could use the pile of 48 variants I have laying around. Instead, I'm out $100+ for what will basically end up in a drawer at the end of the semester.
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I feel sorry for you to the extent that you could probably do most of what the TI89 can do on the HP48s that you already own (though I think you'd need an HP49 or 50 to equal or beat it in all areas), but I'm afraid that I can't agree that the TI89 is junk! I remember being astounded when I got mine, both by how much it could do and by how easy and intuitive I found it to use. At that time I didn't have any HP machines (that has changed now!) so perhaps that explains our different reactions, but I'm afraid that I still love it. Apart from the lack of RPN, what bothers you about it so much?
I agree with you that a course should specify what a calculator is required to do and then leave it to the students to choose any model that fits the requirements. Tying a course closely to a particular calculator seems odd to me, although I realise that it is common (at least in the U.S.?)
Nigel (in the U.K.)
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I unfortunately don't find it intuitive at all. To me, a scientific calculator shouldn't hide all it's primary functions in menus you have to dig for. Luckily I bought it at Walmart. If I end up not using it, can use something else, then I'll take it back. It was an extra $110 I really did not want to spend this semester. Definitely a new record for school expenses (books and misc).
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I liked (and still like!) two main things about it. First, the ability to copy previous answers and inputs directly into the new command line. Making exploratory calculations using this editor is arguably even easier than with RPN, and I don't say this lightly! Second, the brave decision to devote four primary keys (X, Y, Z, and T) to onecharacter variables. This makes algebraic expressions so much faster to type, and algebra was/is one of its main selling points.
This decision means that sin, cos, and tan are shifted functions (and log to base 10 is missing entirely from the keyboard, I think), but I felt that this was a price worth paying. I understand that others may feel differently!
In any case, make the most of a bad job and enjoy the machine. The algebra in particular is fun!
Nigel
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Quote:
Tying a course closely to a particular calculator seems odd to me, although I realise that it is common (at least in the U.S.?)
Look at it from the teacher's perspective. If they require a calculator, then they will need to answer questions that students will inevitably have. So rather than becoming experts in several calculator models, the teacher learns one model and then requires that one for the course.
Quote:
This decision means that sin, cos, and tan are shifted functions (and log to base 10 is missing entirely from the keyboard, I think), but I felt that this was a price worth paying. I understand that others may feel differently!
If HP provided keyboard overlays for their calculators similar to the HP 41, then this issue would largely disappear. Each of us would assign the functions that we use most often to keys and that would be the end of it. To me, the lack of overlays seriously impairs the usefulness of assignable keys.
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Quote:
Tying a course closely to a particular calculator seems odd to me, although I realise that it is common (at least in the U.S.?)
Look at it from the teacher's perspective. If they require a calculator, then they will need to answer questions that students will inevitably have. So rather than becoming experts in several calculator models, the teacher learns one model and then requires that one for the course.
Perhaps my memory is really failing me and I am starting to remember things that didn't happen but I seem to recall earlier posts in this forum that noted that some professors insisted on the use of RPN machines in their courses.
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Quote:
Look at it from the teacher's perspective. If they require a calculator, then they will need to answer questions that students will inevitably have. So rather than becoming experts in several calculator models, the teacher learns one model and then requires that one for the course.
Fair point, although they could still say "Use the preferred model and I can help you; if you choose to use anything different you can, but you're on your own." I personally teach Physics (ages 1118), for which any basic scientific calculator is fine, and I know that the maths department in my school is equally relaxed. In practice this means that nearly all the students have the Casio FX83 or its close relatives; here in the UK it is very rare to see a student with a TI calculator, and HP (as a calculator manufacturer) is unknown.
Incidentally, I showed one of my classes the HP300s. Functionally this is a clone of the Casio FX83, but it looks gorgeous in its elegant blue casing. From their reaction it's clear that if the HP had been next to the Casio in the shops they would have chosen the HP!
Nigel
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Any calculator that has as many functions as the TI89 would have to have most of its functions in a menu. The HP50g is the same way. Worst come to worst, sometimes I'll use a graphing calculator in conjunction with a cheaper scientific that does have all its functions on the keyboard. That gives the best of both worlds.
I think the TI89 is a great calculator. I don't know what sort of class you're using it for, but if you have to derive expressions, as opposed to just crunch numbers, it can be tremendously useful, and a huge time saver. I only wish I had gotten a CAS calculator earlier.
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Quote:
Apart from the lack of RPN, what bothers you about it so much?
I'll respond to that one...it's cumbersome to use. Consider the following points:
1. The command line on the TI89 is a tedious environment for anything but the simplest of expressions. It's single line format requires you to add parenthesis for groupings that would be implicit in other notations. Although the TI89 has "pretty print", you will note that you don't get to see your expression displayed in pretty print until you're done with the problem and it goes into the history stack (so you can then confirm that you entered it wrong!). 2. Why is there no 1/x key on the 89? My theory for that is that TI viewed a 1/x key as a concession to the superiority of postfix notation, so they just omitted it. Think about it...taking the reciprocal of anything with terms in it requires you to scroll to both ends to add brackets, then key in either "1/" in front, or "^1" behind, and finally hit enter! In fact, any unary function you want to use in a follow on calculation requires you to use this "keystroke happy" technique. 3. Want to use the matrix writer on the 89? You must first assign your matrix to a variable, and then specify the dimensions before you're allowed into this application. Even after all that, you can't put your matrix onto the command line, only it's variable name.
I could go on, but I think I've made my point; this machine just confounds you with (many) extra keystrokes and convoluted logic at every juncture. I honestly think most people that use it do so because they just don't know any better.
...but I digress...
Best regards, Hal
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Hal:
You wrote:
Quote:
Why is there no 1/x key on the 89? My theory for that is that TI viewed a 1/x key as a concession to the superiority of postfix notation, so they just omitted it.
As far as I can tell from my collection TI introduced the use of x ^{1} in place of a 1/x key when they introduced the Equation Operating System with the TI68 and TI80. TI's subsequent graphic calculators from the TI81 through the TI86 and the Voyage 200 all have an x ^{1} key instead of a 1/x key. I can't explain the omission of either a dedicated x ^{1} or 1/x key on the TI89. Maybe there really is a bogeyman behind every bush.
Palmer
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My take on your three points:
1. What you say is true; however, the big advantage of the command line approach is the ready availability of previous inputs and outputs. For complicated expressions I find the advantage of this outweighs the extra typing. It is rarely necessary to assign results to a variable, because you can simply scroll back to them when needed. I could really fly on this machine!
2. The omission of the 1/x key is odd, but there is a (postfix, of course) ^(1) function in the catalogue. (I much prefer this to the prefix INV() function that HP use in algebraic mode.) Assigning this to the custom menu allows access to it in two keystrokes (plus enter if you want to see the answer, of course!).
3. You are correct that the matrix editor isn't as elegant as the one on the HP48/49/50. On the other hand, you can type a matrix directly into the command line if you want to, and specifying the dimensions when using the editor isn't really so hard.
Like you, I've used lots of calculators and for me the TI89 is one of my alltime favourites. It's got an infinity key, for heavens' sake! How cool is that?!
Nigel
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Quote:
I agree with you that a course should specify what a calculator is required to do and then leave it to the students to choose any model that fits the requirements. Tying a course closely to a particular calculator seems odd to me, although I realise that it is common (at least in the U.S.?)
Nigel (in the U.K.)
I worked for TI for a few years (in semis, not calcs), but I can tell you exactly why classes are like this in the US. TI spends most of it's money in the calc operations on sales/marketing, and the main marketing is creating free course materials for high school classes with a TI calc as the star.
Teachers get all of these learning materials free, and a free TI calc. They spend millions doing this, hence the penetration into the educational market. The calc division at TI is small, has few people, is a spot on TI's income statement, but the margins are obscenely high.
You can liken this a bit to other professions where you're heavily solicited by a company and then you recommend that product. Good example is in the pharmaceutical biz; docs get bombarded with salesdroids/literature/freebies/etc., and it does influence what prescriptions they write.
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It was upposedly required for both our sons too, but I had the older one just use my old TI59 and he got through just fine. My wife got one for the second son, but the model again proved to not matter, and he could have just as easily used any basic nonprogrammable scientific. Both of them said what most kids used the required calc for was playing games while looking studious.
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I took a lot of flak for rating the Ti89 over the Hp 50g in my calculator review.
http://www.rskey.org/buyguide.pdf
However, the Ti89 is the natural upgrade path for the Ti83/84 line (which 90+% of high schooler’s use) and most people do not know or want to adopt the advantages of RPN. Since most people who buy graphing calculators wouldn’t switch over to RPN on the Hp50G, the Ti89 is a better algebraic calculator and I was forced to endorse that calculator from an objective view. I noted that trig functions (and other often used functions) are second shifted functions.
However, a flaw of the Hp 50G (that is not realized or noticed by RPN users) is the poor units’ conversion and the flawed vector functions / features in algebraic mode.
For RPN user’s that use the Hp50G for common vector math, put it in algebraic mode and try your hand at using it. If the Hp50G had implemented its algebraic function set better, I would have happily endorsed it as the superior calculator.
That left me with the dilemma of recommending a superior (Hp50G in RPN mode) calculator to an audience of 80+% that would not use it in RPN. Therefore the superior calculator for the normal algebraic user is the Ti89 for the majority of applications. The La’Place and Fourier transforms functions of the Hp50G can be of use to some of these users’ but the majority are best served by a Ti89.
Power user’s often augment their high end calculator with a Math package as well or often bypass the high end calculator market altogether. With the popularity of notebooks and low cost math software, this is certainly another option.
I welcome positive feedback from my knowledgeable friends on this review and will take serious offense to wild, unsubstantiated, biased, ridiculous criticism from all other crazy fanatics. However, every so often, I sometimes listen to the crazy fanatics too. ;o)
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Greetings from Puerto Rico.
I agree on the TI89 as a better algebraic calculator to the HP50g.
I wonder why HP did not make the algebraic CALC mode like the HP71B on which the intermediate answers appeared when the close parenthesis key is pressed so you can follow and pinpoint errors better. That's will be a definitive advantage.
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I've been out of school for a long time (30 years), so I'm wondering what sort of math in involved here? I realize calculators have far greater capability now than they had when I was a student. We were were just using them for trig, stats and such in the late '70s, and almost everyone had a different calculator. (Ahh, there were so many choices in those days.) Nobody expected a teacher to know a particular calculator, and math wasn't taught as "keying a recipe into a calculator". The calculator was just for solving the problem  however you chose to do it.
I understand that it can be challenging for a student to learn math that is new to her/him, and then immediately have to figure out how to use a particular calculator to solve problems. But still, it seems like the learning process should not be dependent on a student knowing which combination of buttons to push in order to actually solve problems. The understanding of the concepts should be largely independent of solving a particular numerical example.
So... as long as you take responsibility for understanding your own calculating device, why does it matter to an instructor which one you use? Do assignments and exams consist of indicating to the instructor which button you push to solve the problem?
I know, I'm a dinosaur, and I've been out of academia for a long time. In my day, understanding the math and understanding the tools were separate joys, and they were both truly joys.
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Manatee, I say you are right on target... for college instruction, for sure. My guess is, the middle/high school teachers on here will say its much different in that environment. My wife teaches high school English, and from the anecdotes I hear, there are so many challenges to teaching theses days, that any simplification possible is welcome, to include standardization of calculators.
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I'm in my fifth year of teaching middle school math, and the presence and use of calculators in the math classroom is totally up to the teacher. Some teachers allow them and encourage their use, some don't. I don't know of any teacher in middle school that "requires" students to have a calculator, much less a certain brand. High school is probably different.
Most of the "older" teachers (who were in school before calculators were even invented) don't use them very much at all, even the simple 4function ones. Most of the "newer" teachers allow them, but can't really answer students' questions regarding calculators (teachers, unlike us, are not geeks, typically).
The good (or bad, depending upon your perspective) news is that kids are still learning and practicing math concepts much as we did when we were in school.
Except, of course, 1 is not prime today.
: )
Don
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Wow! how things change. I was in High School in the early 70's. I used a slide ruler. What a pain when the battery would die!
Joe
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Me too, Joe! And I seem to recall it had a LOT of vertical lines in the display, too! Appalling! Such lowend computational devices  how did we EVER get by?? :o)
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So did I. Trained us guessing orders of magnitude, and taught us about error propagation. Beyond that it was tedious but we didn't know better.
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One thing we didn't have in the slide rule days was professors dictating which manufacturers machine to use. They did encourage us to get a loglog trig as soon as we could afford it. Meter readers were encouraged to get a loglog vector.
I didn't know it at the time but there was one advantage to using the Mannheim slide rules which had a "well" behind the slide. Many years later I saw one of those at a garage sale and another person told me that he never would have passed physics without it. I asked why. He told me that he used the well as a crib sheet for formulas that he had trouble remembering.
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I think the idea of how to use them in the class is somewhat for the graphing, and perhaps, also to check your solutions. While the calculator isn't going to solve the problems step by step, it will let you know if you properly derived the trig function as an example.
In the first class, which wasn't much more than going over the syllabus, the professor acknowledged that the requirement is forced on him by the math department, but he could personally care less if we had one or not. He's going to want to see the problems worked out by hand, and said that while some teachers in the department use them in class, he does not.
Really, for checking answers, I can probably just as easily use something online like Wolfram Alpha.
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The big problem with the TI89 is that it's running an OS that was specifically designed for a device with a full QWERTY keyboard  namely, the TI92. Thus there's not a lot of thought to menu usability, since you can generally type function names more quickly on the 92. By putting this OS on the 89, you end up with a calculator that's actually pretty good, albeit algebraic, but which is crippled with terrible usability as a result of severely reducing the number of keys, and falling back on menu structure that wasn't that great to begin with.
My advice is to skip the 89 and just get a 92+ or Voyage 200. They're the same thing, minus the suck.
