## The Best Graphing Calculator on the Market? 724 724

aaronbeekay asks:

*"I'm a sophomore in high school taking an honors chem course. I'm being forced to buy something handheld for a calculator (I've been using Qalculate! and GraphMonkey on my Thinkpad until now). I see people all around me with TIs and think 'there could be something so much better'. The low-res, monochrome display just isn't appealing to me for $100-150, and I'd like for it to last through college. Is there something I can use close to the same price range with better screen, more usable, and more powerful? Which high-tech calculators do you guys use?"*
## PDA? (Score:5, Insightful)

## Re:PDA? (Score:5, Informative)

## Re:PDA? (Score:5, Informative)

I gave away the first PDA I got because I could not figure out a way in which it would possibly assist me more than carrying around a pad & pen.

But the TX does everything. It's got a SD slot, so you can carry around full length movies, a million MP3's...

Excuse me, I have to go hug my palm.

## Re:PDA? (Score:5, Informative)

## Re:PDA? (Score:4, Informative)

http://www.mobilevoodoo.com/power48.htm [mobilevoodoo.com]

## Re: (Score:3, Funny)

enter freeware

enter +

awesome hp48 emulator

hmm actually, I think it would be better to say

palm [ENTER]

freeware [ENTER] +

awesome hp 48 emulator

In other words

4:

3:

2:

1: palm [ENTER]

4:

3:

2: palm

1: freeware [ENTER] [+]

4:

3:

2:

1: awesome hp 48 emulator

## HP 48GX is an Amazing Calculator (Score:5, Informative)

I absolutely agree. The HP48GX is an amazing calculator. Reverse Polish Notation (RPN) rocks...you don't need to enter in brackets with complex expressions which probably makes it 20-30% faster than other methods. The calculator uses a stack system for its calculations. To add 2 and 3, type 2 and hit enter to put it into the stack. Then press 3 and hit enter...3 also appears on the stack. Then press +. This adds the bottom two entries in the stack. With complex expressions, you start on the innermost brackets and work outwards. Because your answers are always visible in the stack, it is remarkably easy to evaluate expressions without ever rounding more than the calculator's precision.

The stack doesn't just work for numbers. It is possible to enter in many types of objects. Enter two matrices or vectors into the stack, then press +, -, x, or / and the calculator will add, subtract, multiply, or divide the two matrices, just as if they were two numbers. To find the inverse matrix, enter it into the stack and press (1/x). Complex numbers are easily handled by entering them as vectors.

The main weakness of my version is that it is a bit slow when doing things like graphing. The origin of this problem lies in HP's neglect of this product. HP used to be a highly innovative and inventive technology company. They made products that no one else imagined making, things that were designed to meet the requirements of technical professionals like engineers. Then the bean counters/MBA's took over. They sold off most of HP's innovative divisions (Agilent Technologies for example) [wikipedia.org] and became primarily a maker of bog standard PC's. They stopped making the 48GX for a while, but brought it back after a loud outcry. The new version was however not quite the same as the old version. It feels cheaper than the older calculators...it doesn't quite have the same solid feel. Bloody corporate bean counters! HP has been losing money for much of the time since they took over.

It is a shame that HP hasn't updated this calculator. With a newer processor, and a few interface updates, this could truly be the ultimate calculation tool. It is still great, but if it were a bit faster with a more polished interface, then it would be perfect.

## Re:HP 48GX is an Amazing Calculator (Score:4, Informative)

## Re:HP 48GX is an Amazing Calculator (Score:4, Informative)

Also, for chem it's perfect. Often you need to add up different steps of a reaction seperately then sum them. With RPN, there's no retyping! Also, there are tons of libraries including a molecular weight calculator and much much more. And there's even a remote control program for the built in infra-red tranceiver so you can mess around with the televisions in class

I'm happy to hear that HP has a newer faster version out. It was a little slow on graphing, but only in high precision mode (when you need to look up something on the curve, it'll calculate all the values based on an interval of x you specify, such as

## Re: (Score:3, Informative)

I bought mine when I was a freshman in high school. It carried me through 4 years of high school, 5 years of college, and even though I haven't needed to use it in a long time it still works after 5 more years in the workforce.

That thing was made like a tank. None of that cheap flimsy crap that the TIs were made out of. And if you don't care about the expansion cards (I never found one that I needed), and you were handy with a soldering iron you could upgrade your G to the same

## Re: (Score:3, Informative)

No need for the second enter.

## Re:PDA? (Score:5, Funny)

## "Regular" calcs are not PN calcs (Score:3, Interesting)

The "regular" calculators with equal sign are not PN calculators.

## Re: (Score:3, Funny)

## Re:PDA? (Score:5, Informative)

Personally, I think the TI-89 is the best graphing calculator you can get. It's got very helpful algebraic functions that solve equations, factor polynomials, etc. It even does indefinite integration and differentiation of functions (very useful for checking your work when you take calculus, the TI-83 does no such thing). Everything looks nice and shows up just like you would write the algebra, so data entry is much easier. Previous calculations are stored in memory and you can just scroll up and select an answer or the calculation, and it will show up in the entry line. Very useful for complex calculations. It has the capability to display exact values, ie for cos(30) most calculators will give you

To be honest, you only really need a calculator until you leave high school. Getting anything fancier than a TI-89 is a waste of money. In college, a simple scientific calculator will suffice for lower division classes. If you go into engineering you will be doing serious math by hand and serious calculations by computer (MATLAB or FORTRAN). No more "graphing" in the sense of the primitive capabilities of graphing calculators. Once you've learned about all the things they can do, you move onto more complex functions and calculations, more complex data sets, and you just don't need to use a calculator to figure out what y = x^2 looks like. I imagine science and mathematics is the same, except maybe with Maple or something.

## Re:PDA? (Score:5, Informative)

## Re:PDA? (Score:5, Informative)

## Re: (Score:3, Informative)

its been a while since i took an AP/SAT test though.

## Re: (Score:3, Informative)

For the SAT, a calculator does not help much. A standard 4-function calculator is as useful as a fancy TI-89. Most of the problems involve l

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## Re: (Score:3, Funny)

## Re:PDA? (Score:5, Informative)

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## Re:IA32 + Matlab R13 (Score:4, Informative)

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## Re:IA32 + Matlab R13 (Score:4, Insightful)

## Re: (Score:3, Interesting)

I'm not sure about the models from only 12 years ago, but the HP-41C I bought around 1982 or so still works perfectly. Truth be told, it works better than new, thanks to it's accepting add-on modules (of which all four slots are permanently full). The

## Re:IA32 + Matlab R13 (Score:4, Informative)

Thus, in order to use Octave as a graphing calculator, you would have to use, say, a standard Linux distro. It presumably wouldn't run on a 150$ handheld.Actually, back when I was in school, I had Octave + Gnuplot running on my Sharp Zaurus.

Yes, you really can run it on a $150 handheld.

Also worth mentioning is that there are convenient packages for Windows which include Octave and Gnuplot.

Here are some links:

## TI 89 (Score:5, Informative)

## Re: (Score:2)

## Re: (Score:2)

In my maths course, no calculators are allowed in *any exam*, full stop.

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Math is about more than

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## HP (Score:4, Informative)

I have an HP-48GX and it served me well through high school and four years of engineering school.

## Re:HP (Score:4, Informative)

Personally, I decided that I did not actually need the graphing features so now just use an HP-33s. It's pretty solid and does everything I need. For me, in the real world, I found that the graphing capabilities of the calcs were not useful -- if I needed to plot, I would do it on a computer. The graphing calc was just not a substitute. I suppose the programming might be more flexible on the bigger calculators as well, but I have not once found myself wishing for one since high school.

(for reference, I've worked as an electrical engineer/programmer and am now a graduate student in physics)

## Re: (Score:2, Interesting)

Personally, I decided that I did not actually need the graphing features so now just use an HP-33s. It's pretty solid and does everything I need. For me, in the real world, I found that the graphing capabilities of the calcs were not useful -- if I needed to plot, I would do it on a computer. The graphing calc was just not a substitute. I suppose the programming might be more flexible on the bigger calculators as well, but I have not once found myself wishing for one since high school.I must agree with you

## Re:HP (Score:5, Insightful)

For anyone who is planning to be a physical scientist or an engineer, a powerful calculator is a handicap and will hurt you in the long run. The ease of solving problems in low level math courses will come to haunt you when you take a course that includes something like Laplace transforms or complex analysis.Spoken like someone who doesn't know how calculators are intended to be used. As I have told many a math student in my classes, calculators are no substitute for understanding how to work a problem. They are

labor saving devices## Re: (Score:3, Informative)

The computer connection is something I have longed for. My 50g uses USB and draws it's power from the PC, so it would be great if I could use it as a more efficient way to in

## Re:HP (Score:4, Insightful)

The TI-89 can do anything taught in a math course well into a 300 level course, possibly four hundred.And a trained human can do anything taught in any math course. To effectively use the TI-89, you have to (a) understand the problem, (b) know how to translate it into a form manageable by the calculator, and (c) enter the problem in such a manner that a meaningful result is produced.

Punching the equation into the calculator and getting an answer *even if it is only a small part of the actual problem* reduces drastically your ability to spot an error in any given step in a larger calculation.Absolutely. But guess what? Nearly ANY institution that relies on computers does exactly this, every day. Do you really believe that there are paper audits of every computation involving every bit of datum used by NASA, Microsoft, AT&T, the NSA, etc., and that those audits are actually examined for errors?

So, restated: knowing how to work a problem is not enough. If you are teaching your students that it is, I believe that you are doing them a major disservice. Being so familiar with the problem that one can spot a mistake right in the middle of it, while focused on actually solving the problem, with nothing more than a pencil and basic scientific calculator at hand.. that is knowing enough.A couple of points here:

1) Familiarity with a problem is a luxury that sharp undergraduates may enjoy. But, in the real world, there isn't a great demand for people to solve mathematical problems that have already been solved --- those problems can be repeatedly solved by computers.

2) You tacitly assume that students/graduates know how to use a calculator to solve the problem. In my experience, this is rarely the case. I won't elaborate on this except to say that until you've taken a course in numerical analysis, you really don't know how use a calculator.

## Re: (Score:2)

Personally, I'd still like my TI-89 even if I never graphed anything on it again. I just really like being able to see the whole expression I type in (not to mention that it's "pretty printed").

## I don't think they sell it any more (Score:2, Informative)

## Re: (Score:2, Insightful)

They are rugged. My old one got dropped all over the place, crushed in a book bag on numerous occasions, you name it. It took some heavy duty organic solvents to finally kill it dead.

They have a truck load of

## Re:HP (Score:5, Interesting)

strong statement as to their durability.

## RPN Baby! (Score:5, Funny)

There is just something fundamentally appealing to owning a powerful calculator 90% of the population can't even add two numbers on...

## Re: (Score:2)

## Re:RPN Baby! (Score:5, Interesting)

A friend of mine at MIT had an HP-48, and I had a TI-81, we used to do a lot of engineering problem sets together and would often race on entering calculations. Averaged over time the competition was a draw. Although the HP-48 definitely wins from a "cool" factor perspective (where cool=geek).

Speaking of the TI-81, I bought mine in 1991 for $82, and I'm still using it every day.

## Re:RPN Baby! (Score:5, Funny)

A few years ago I was doing the taxes and I reached for it to do some arithmetic and she nearly broke my hand. But that might just be her Eastern European sternness coming through. I got a little too enthusiastic on one of our first dates and almost lost the hand that time, too.

## Re: (Score:3, Funny)

## Re:RPN Baby! (Score:4, Interesting)

Then your friend was slow -- or you were very quick. Take some complex expressions and write out the keystrokes required in RPN and infix notations, and you'll see that RPN almost always wins. However, the big win isn't the keystrokes, it's the mental complexity. With infix, you have to maintain too much state in your head -- with particularly nasty expressions, you basically have to keep track of the whole expression in order to enter it all correctly, closing the parentheses at the right times. With RPN, you think about it differently, "collapsing" subexpressions as early as possible, minimizing the amount of you have to hold.

My friends and I ran a series of tests in college, specifically to determine which was more efficient. Not only did the postfix evaluations typically have 10-20% fewer keystrokes, the person writing the postfix version typically finished writing the evaluation while the person writing the infix was still figuring out how to express it. What finally convinced the doubters in our little experiment to buy HPs was that the infix evaluation got the wrong answer much more often than the postfix evaluation did -- usually because of some miscounted parentheses.

RPN is faster, easier and more accurate on complex expressions.

## Re: (Score:3, Insightful)

## TI-85 (Score:2)

## Re: (Score:2)

## HP 48GX (Score:2, Informative)

## Ebay yourself up an old TI-82 or -86 (Score:4, Informative)

My only difficulty was an occasion scramble to find where some higher level functions were, as the rest of the class had newer calcs and they couldn't help me out.

Just do yourself a favor, get an older calc (with an instruction book), and spend the rest of the cash on ice cream.

## Dunno (Score:2)

However, and far more importantly... I got a free solar powered calculator today and I'm unaccountably pleased with it.

## Re: (Score:2)

Also, I got to keep it on a lot more tests than the graphing calculator people...^_^

## Ummm, HP 48G (Score:4, Informative)

This is one realm where you want a tool, not a toy - if you want something flashy and shiny with a nice screen and pleasing UI, save your pennies for an iPhone or something. If you want something that does math, and does it damn well, buy an HP calculator.

PS - I guess this doesn't quite fit your answer as according to Wikipedia they stopped making them back in 2003, so it's not really "on the market" any more. They are currently selling HP-49 series, which is still better than TIs but just isn't built like the 48Gs (the tactile feel of the keys really does matter on a device where punching numbers is the main use). Still, I'm guessing that 30 seconds with eBay and you'll find 48G's...

## Bah! (Score:4, Insightful)

Classic HP 15C. Graphing is for sissies. Best form factor ever (sideways, punch with both thumbs)

Maybe a 48SX if you really need graphing.

RPN forever!!!

## Let the Flaming Begin (Score:5, Insightful)

Especially when the HP48GX is the clear winner...

/me ducks## Re: (Score:2)

## Re: (Score:3, Insightful)

...they had been forced to use TI calculators in high school, and that was what they were used to.

## Why you should still consider a TI 89 (Score:5, Informative)

## Oh come off it. (Score:4, Interesting)

* Quick factoring of integers, radicals, polynomials

* Term collection and simplification

* Handling of arbitrarily large values without loss of precision (esp w.r.t. factorials)

* Substitution of variables or expressions in general formulas (user-provided function)

It really can't "solve" very much other than 4th degree polynomial roots. It's really just there to help you manipulate a complex expression without making a mistake (but you really need to be doing the manipulations... which of course requires a bit of knowledge, don't it?)

BTW I distinctly remember adding the incomplete beta and gamma functions to my TI-89, and I think error function too. They would simplify to trivial expressions if they could (to promote further manipulation) or returned numerical solutions if so coerced. I thought it was pretty slick...

## The TI-89 *will* do some impressive things... (Score:4, Informative)

Sure, Mathematica or Maple will run circles around the TI-92/89, but I recall that the TI-92 could actually do some pretty impressive things. I certainly found that it would symbolically integrate some things that I otherwise would have used an integral table for. It could also do some very hairy algebraic manipulation (and often reducing the result down to something nice). BTW, I don't recall just what basic functions it can integrate, but it certainly can do Gaussians -- I used my TI-92 extensively for prob/stat stuff where I was calculating Gaussian integrals quite frequently. I believe the TI-89 will do the same stuff (someone please correct me if I am mistaken), and it won't be so ridiculously bulky.

I finished my Ph.D. a couple of years ago so it's been quite a while since I've been in any situations where I've been constrained by test taking considerations. =) I use a computer for all that stuff these days. (Which certainly makes sense, since I'm a computational scientist by profession.) But from what I recall of the days when I was frequently using calculators, I don't think you can go wrong with the TI-89, especially since its use is explicitly allowed on a bunch of standardized tests in the US.

BTW, I also used an HP48G extensively in college. I've still got it and use it occasionally, and it has some nice features. And, yes, once you get used to it, RPN is pretty clever. I see a lot of people championing it in favor of the TI calculators on here, but I mostly think that's because of the geek style points it confers. The HP48G series is way better than the TI calculators that came before the TI-89/92, but compared to the TI-89/92 I think the HP48G series really show their age. My 48G is *way* slower to do complicated calculations, much slower in drawing and manipulating graphs, and its symbolic manipulation capabilities are a joke.

## HP 48 4-Life!!! (Score:5, Interesting)

RPN is very nice for long equations. Once you get used to it, you'll be more accurate and efficient. You'll never want to go back to algebraic entry. It has a lot of features, and still stands up pretty well to modern offerings. Unless they've made calculus problems a lot harder, you won't need anything more functionality wise.

The built in equation library is very nice. There is a plethora of available programs to download. The IR sensor is just cool and the keys have the best tactile feel of any calculators ever, and the batteries last about 20 months. Oh, and you could probably dip it in motor oil, and it would still work. The screen while having good contrast, is very fragile however. That's one bad thing.

Expect to pay $250 on ebay for a 48GX unless you get lucky. (The 128K expandable model. Original MSRP was $159 I think) You can probably get a 48G (32KB non expandable model) in your price range though.

## Re: (Score:3, Funny)

Don't know about your HP-48 (which I own too, by the way), but one day the tomcat puked right onto my old HP-32S, which it didn't appreciate at all. I had to disassemble it (try that with the tank-like construction of HPs, took me me 2 hours) in order to clean it and make it work again.

## A few options (Score:2)

If yo

## Mathematica+UMPC? (Score:2, Redundant)

Special purpose hardware is dead.

## Re: (Score:3, Insightful)

nbsp;

Seriously dude...he wants a handheld calculator, and you respond with UMPC with Mathematica installed on it. Wow.## You don't have much choice (Score:2)

waybehind the TI-92 many areas and I don't think there has been a new model since. If you have to graph a differential equation on an HP, be prepared to wait. The TI-89 has symbolic calculus, algebra, differential equations,## Just get the TI-83 (Score:2, Informative)

But I am a recent University graduate. I think I had something like 1 or 2 classes that allowed me to bring a Ti-83 into the test with me. Most of my math based classes specific

## HP-50G (Score:2, Informative)

## TI (Score:2)

## Durability (Score:4, Insightful)

If you do get a 48GX do be careful protecting the screen. The carrying case doesn't provide enough protection - I lost one because of that.

## Boring? Maybe. Care? No. (Score:2)

Better rethink why you are buying a calculator. I normally use my TI-89 for.. well.. calculating. I don't use it to play games (get a DS or PSP for that), listening to music (get an mp3 player), or doing complicated analysis that requires a large screen (Maple for the PC, or may

## HP 48 (Score:3, Insightful)

The bad news is that HP's calculator division ain't what it used to be. The good news is that almost all HP calculators are extremely durable. I have personally worn out multiple HP calculator keypads, but it took about two years of heavy use to wear out each one. And by heavy use I don't mean mere homework... I mean 8 to 10 hour days at my job, where 60% of my job was to crunch numbers. (Yes this job was better suited to other hardware, but I worked with what I could get.) If you can find a used one that works at all, it should prove very durable.

If you can find one, a 48G or 48GX would be excellent.

(I am less impressed with the newer HP49 and its derivatives. It seemed to be a step backwards in usability to me, mainly because of the keypad layout. The all-important "enter" key is in a bad spot, and not double-sized.)

## WHy any? (Score:2, Insightful)

## Re:WHy any? (Score:4, Insightful)

## Re:WHy any? (Score:5, Interesting)

I'm also a Ph.D. student in math (defending my dissertation next month), and I've found the exact opposite to be true. There's no better way to develop a deeper understanding of something than to play with it. As regards calculus and functions, this means plotting functions, composing them, zooming in on them, adding them, differentiating them, multiplying them, etc. This is especially relevant with polar and parametric equations, which can take some time to get the hang of.

The newer calculators even let you play with systems of differential equations and trace out solutions, flow lines, etc. What a great way to learn to visualize otherwise abstract concepts! If students would just sit and play with equations and see what the solutions would look like, they would have a much better grasp of what to expect when they encounter something new. Otherwise, it can tend to be a matter of memorizing a cook book of solution techniques.

Of course, there are times when the calculator can be a hinderance. In particular, the built-in symbolic differentiation and integration can become a crutch. (On the other hand, it's a great way to check your answers.) However, most of the associated problems can easily be dealt with by properly writing your curriculum. (e.g., giving calculator-free exams to test differentiation knowledge, splitting them into two-part exams (without calculator, then with calculator), giving weekly 5-minute self-quizzes, etc.)

At the end of the day, a graphing calculator is just another tool that can be used to help or hinder education. How it goes depends on a combination of student motivation and the leadership and guidance they receive from their professors and teaching assistants. (i.e., you) -- Paul

## Re: (Score:3, Interesting)

## TI nspire (Score:5, Informative)

## Re:TI nspire (Score:4, Interesting)

If you can prove me wrong, and show that the nspire is as accessible as the TI-85, I might buy one just for day-to-day field engineering needs.

## Qonos (Score:2)

It's amazing how much computing power there is now compared to my 4-bit processor hp48 (it still rocks). If only there was a nokia770-like device with a decent keyboard, it would make a great calculator platform.

## Old School - TI-35 Plus (Score:3, Insightful)

And it only cost me about $25. I don't know if there is a modern equivalent.

I do agree that HP's postfix is easier to use, but I always used paper for my intermediate steps, which was usually required anyway.

My advice, forget the graphing and other crap. If you need to write code for your problem, you need a laptop.

Dave

## No you have to use TI (Score:4, Interesting)

## TI-85 (Score:3, Informative)

## I don't get the graphing stuff - can someone help? (Score:3, Interesting)

The only time I have ever seen it used is to show the multple zeros of an equation, but even that was just a curiosity. If you can't get a pretty printout, why bother? Furthermore, you need the exact numbers anyway whenever you want to solve something. If you want to estimate, do it in your head.

Admittedly, I own an HP48, so I use the screen as a visual stack. Again, all of the graphing fuctions are pretty, but not practical unless you happen to be using it for a game, or calendar, or as a help screen in an equation (and if you need a help screen, imo you don't know the equation well enough to be using a calculator).

So, are there really

usefulorcomputationally practicalreasons for a graphing calulator, or does everyone just want them because they are "cool"?## Re: (Score:3, Informative)

## Re:TI 89 (Score:5, Funny)

I disagree. I paid about $300CAD for my Ti-89 and not only is not allowed on tests neither at the grade 12 level nor first year collegeMaybe it's because you're in Canadia. In the US, the TI-89 is explicitly allowed on tests [wikipedia.org] administered by the college board (but not ACT). It's also the reason I bought it, the TI-92 isn't allowed on any tests.

mine's already broken after only about 2 years of seldom use.How odd, I bought mine when it was first release (1998) and it's still going strong. Maybe it's the Canadian weather that caused yours to fail. Also, you're not supposed to use it while taking a shower.

## Re:TI 89 (Score:5, Informative)

I bought my TI-85 shortly after they came out in '92, and I still use it (in my Ph.D. work, nonetheless). It's kind of a tank, and has held up well over the years (all 14 of them - crap I'm old).

I was going to suggest a TI-86, as it's the memory-upgraded 85. The TI-86 is also lacking symbolic math, so it is generally more allowed on tests and in classes than the TI-89, but it does have a lot of tools that the 83 & 86 don't (like simultaneous equations solving and polynomial root finding) that make it very useful.

## Re: (Score:3, Insightful)

Either they're good enough you're not allowed to use them ever, or they just help you with the trivial things, and if you can't figure out what the graph of y=x^2+3 looks like, no calculator in the world will help you do well in even the most basic of first-year calculus classes

## Legal for tests (Score:2)

Then, find the best TI that you can guarantee will be allowed pretty much everywhere -- or better, get your parents to buy it; it's for education, right?

This does not excuse you from having a laptop in college. The TI is for math -- the class and the tests. The laptop is for every class that isn't math. Put your calendar on it, put notes on it, and if at all possible, put your boo

## Don't take notes on a laptop (Score:4, Insightful)

## Re: (Score:2)

Ask around -- ask colleges you're interested in, ask your high school -- what you want is something that will be legal for tests.

Then, find the best TI that you can guarantee will be allowed pretty much everywhere -- or better, get your parents to buy it; it's for education, right?

Yes! Agree 100%. The TI-83+ features are the most that were allowed in my calculus tests (3 years ago). The prof allowed older/less featureful calculators if you wanted to use them, but anything with more features wasn't al

## Re: (Score:2)

## Re:Sliderulers.. what you realy need is a slide ru (Score:2)

Graphing calculators are **WAY** over-rated ... what you really need is nice slide ruler! Remember .. nothing goes better with a slide ruler .. than a nice pocket protector to put it in! (Ok .. I can now get my former boss of my back ... He was always pushing slide rulers on the other engineers).Not only that, but they don't have batteries to run down, or need an AC adapter.

Very useful for when society collapses and needs to be rebuilt.

## Re:Save your money (Score:4, Interesting)

Remember, the generation before yours survived high school and college without the benefit of graphing calculators, and the generation before that used pencil, paper, and tables. Most of them turned out okay.And you never know when being able to do things by hand is going to save your ass.

I recall a physics exam my freshman year of college, fairly simple mechanics stuff: find how long something takes to slide down a ramp, that sort of thing. About 10 minutes into the hour long exam my calculator blew up. Something in the LCD burst, it was a paperweight.

This was the kind of tech school where the professors just don't give a shit about your issues, and where too many missed exams counted against you heavily; leaving in the middle of one without completing it was the same thing. I was fast enough to get everything but one problem finished with 40 minutes to spare even without the calculator. Only problem was that the answer involved multiplying by the sine of an angle.

I had a couple of sin and cos values memorized: 30 degrees, 60 degrees. Had memorized the square roots of 1 through 5 to a few places, and happened to know how to compute those by hand as well.

Ever come across these formulas?

sin(x/2) = ± sqrt([1 cos x] / 2)

cos(x/2) = ± sqrt([1 + cos x] / 2)

sin(a±b)=sin(a)*cos(b)±sin(b)*cos(a)

Well, if you know sin(30) and cos(30), from these you can compute the values at 15 degrees with a few mathematical operations, then 7.5, then 3.75, etc. Build that little table, and then you can add or subtract things together to reach other values, and maybe throw in a little linear interpolation. Eventually I build an estimate answer using this approach that was close enough to get most of the points for the problem. Got dinged for not using enough significant digits, as if I'd made a rounding error, but got most of the credit.

When time was called I was in the middle of trying to check my answer against the results of a Taylor Series computed with Horner's Rule [dattalo.com]. Converting degrees to radians by hand is a snap once you've memorized Pi to a thousand places [youtube.com]...

## Re: (Score:3, Interesting)

I recently got a TI-89 Platinum for use in several science (and calculus >_</) courses over the next few years. Despite the fact that the HP-48 and HP-50 are technically superior, and RPN is the fucking win, I chose the TI anyway, and for one reason: software.

There is TONS of homebrewed software out there for TI calcs, and I'm already relatively familiar with m68k assembly, from coding on my C=64 back in the day (though I'm horribly rusty)

## Re:TI-89 Platinum (Score:4, Informative)

## Re: (Score:3, Funny)

Heh. In high school I wrote a program for the TI 83+ (what we all used) that had the keystrokes for wiping the memory preprogrammed. I'd run that program before the teacher came to wipe the memory, she'd go through and wipe the memory, but she was really just running my program. Basically it was like if I had, in autoexec.bat back in the day, a basic program run which was

DO WHILE 1 < 2

INPUT "C:\>",

LOOP

And when I