I use the TI59, TI30 and the SR50A. I just love the tiny LED displays in these things.
My first calculator was the Casio fx-85s that I got for school, it still works on the first battery.
The retards who designed the Nspire need to be fired with a quickness...all the button real estate at their disposal and not even the common courtesy to make the keypad a proper querty layout.
Doubly puzzling considering they saw fit to extend that courtesy with the Voyage 200.
I know it's been mentioned but I can't fault my 991es plus, especially now I'm using almost all the buttons on it regularly :/
Doubly puzzling considering they saw fit to extend that courtesy with the Voyage 200.
I suspect the non-querty layout is driven by the technicality of "computer" vs. "calculator" as applicable to testing; the inclusion of a querty keypad de facto classifies the device into the former category, rendering it an unauthorized device for many tests in the US...an uncritically retarded game of semantics if you ask me.
Well thanks to this thread I'm getting a Casio CFX-9850G off ebay in a few days for use on that MIT 6.002x course.
For the price of a pint of beer NIce.
Well thanks to this thread I'm getting a Casio CFX-9850G off ebay in a few days for use on that MIT 6.002x course. For the price of a pint of beer NIce.
Oh, don't say that, I remember paying a hundred-plus quid for mine shortly after it first came out -- would've been towards the end of my days at secondary school, and working my way through my maths teacher's engineering maths textbook. Needed to replace my fx-7000GB (which had suffered an indignity and ended up with a smashed screen) and figured "hey, shiny, colour screen and significantly more modern, what's not to like?"
Nice enough machine, the colour display is probably about the best you can expect given the technology of the time, and some of the features are rather nice -- graphically solving inequalities makes good use of the colour, for instance -- but I do sometimes have to spend a moment working out where in the menus a given option is hiding, compared to the rather upfront nature of its simpler brethren!
(Mind you, in more recent years I've picked up a replacement fx-7000GB and an fx-6300G, which I'd used before the 7000, both for very little; the 7000 lives on my desk at work whereas the 6300 hangs around the living room at home. The latter has been what I've been using for 6.002x; I was quite pleased to discover I could still remember how to use the graphics functions to read off values at an intersection, more than fifteen years after I last used that model in anger!)
I use KCalc on my computer (part of the KDE desktop). KCalc does binary, hex, octal, as well as decimal.
And I still use my HP15C, which I have had for twelve years. Got it second-hand. Still works great. I'd like to know if the ones for sale online are part of the original HP models, or if they're cheap Chinese copies. I'd buy another HP15C immediately if I knew it were made by HP.
I have also owned an HP41CX, which is a programmable calcu
lator. RPN is great for hand calculations, I agree. But it's
hard to read the programs when you write programs in it. What I mean is, to debug and to remember the HP41CX programs, I had to draw myself little schematics in order to remember what result was in which register before and after each step of the program and in which memories I had stored which intermediate results! Even with only a couple of registers, programs written for this machine were nowhere as easy to read as those written in a symbolic language, like Matlab, for example. I guess I might feel differently if I were an assembler programmer. But I am not.
Before reading this thread, I'd never heard of VPAM "Visually Perfect Algebraic Method". Does anybody know what is the difference between this and AOS "Algebraic operating system"?
Or is it just the same thing called X by manufacturer A and Y by manufacturer B?
I'd like to know if the ones for sale online are part of the original HP models, or if they're cheap Chinese copies. I'd buy another HP15C immediately if I knew it were made by HP.
The latest 15c Limited are manu. by Kinpo for HP. Battery life isn't as hot, the f'n buttons rattle, no reference on the back side, and diagnostics is different, but other than that, they're fair and worth the purchase imo. If you can pick up a good condition original for a comparable price (fat chance), I'd go for that over the new Limited.
I have a Casio fx-3600P.
It is running on it second battery.
I bought it new around 1980.
Still works perfect.
VPAM is Casios term for having to write out the equation before doing calculations. Its geared towards learning math, but it can be very powerful if the calculators have more processing power, akin to solving complex equations like MathCad.
The cheapo style we first encountered, and comes in say the Windows calculator, is the immediate execution type, where each time you press an operator, the result is given, so if you have to work on complex equation, the user has to translate the math into how the calculator should do it. Its not a problem for 'basic' math like arithmetic, but move into calculus or where more variable are involved, and it get more tedious if not impossible.
http://en.wikipedia.org/wiki/Calculator_input_methodsBefore reading this thread, I'd never heard of VPAM "Visually Perfect Algebraic Method". Does anybody know what is the difference between this and AOS "Algebraic operating system"?
Or is it just the same thing called X by manufacturer A and Y by manufacturer B?
The best calculator is the no longer made HP 42s rpn calculator. I have it in a drawer and bought it 22 years ago for a lovely sum.
I love RPN, its so natural once you start using it.
Mine no longer works as one day I had a full sheet of mdf in the carport and various papers, straight edges etc on top as I was marking out. A friend of the wife arrived and drove up and parked on everything. I went out to find it under her bloody wheel.
A couple days later I went to ebay to find a replacement as they are no longer made. I couldn't find anything second hand under ~ $250 USD.!!
The manual is still a nostalgic read though
Long ago, back before the Internet created HP collector insanity, when HP discontinued the HP42S, Walmart put them on sale for something like $15! I bought one, and now realize I should have bought all of them!
For me, I prefer the HP11c/15c, I think because the 11c was my first RPN calculator back in 1987. I've used it so long that it has shaped the way my brain works. It still has the original batteries
The best calculator is the no longer made HP 42s rpn calculator. I have it in a drawer and bought it 22 years ago for a lovely sum.
I love RPN, its so natural once you start using it.
Mine no longer works as one day I had a full sheet of mdf in the carport and various papers, straight edges etc on top as I was marking out. A friend of the wife arrived and drove up and parked on everything. I went out to find it under her bloody wheel.
A couple days later I went to ebay to find a replacement as they are no longer made. I couldn't find anything second hand under ~ $250 USD.!!
The manual is still a nostalgic read though
Me, I have an HP15C, more than 20 years old and still working.
Two things no one has talked:
1) RPN is easy to lean if you use the right approach:
always write first the number and after what "the number is doing" to the others you have already written.
Algebraic:
(3+2)*(5-2)
Slowly :
3 Enter the 3 is not doing nothing
2 + the 2 is to be added to the 3
5 Enter the five is doing nothing
2 - the 2 is to be subtracted to the 5
* and the result will be multiplied
In RPN all in one line
3 Enter 2 + 5 Enter 2 - *
2) What can this strange notation can bring as benefit?
All the new operands/routines that you define work the same as the "native" operands of the calculator.
Using // for the parallel of resistors lets calculate ( all in ohms!):
(((3+4)//(5+2))+3)//10
Two series of two resistors in parallel, then a fifth ( 3 Ohms ) in series and a sixth (10 Ohms) in parallel.
First the parallel can be programed in RPN as:
[Begin_Routine] 1/x x<>y 1/x + 1/x [End_Routine]
You only need 5 keystrokes and the [Begin_Routine] [End_Routine] stuff (specific to each calculator).
Now having assigned the Routine to an suitable key ( we will call it // ) to do the above calculation you will only need to press:
3 Enter 4 + 5 Enter 2 + // 3 + 10 //
Now, if you have an HP15C and want to do the same with complex numbers, you don't have to do nothing more.
Yes. What you have done, already works with complex numbers!
See, that's why some guys are mad about RPN.
So grab an RPN calculator emulator for your favorite OS and try it.
Greetings
paf
ti89 of course. I cannot imagine using anything other then a Ti89. They are truly a modern marvel.
Units? Check
Calculus made easy? Check
programs that deal with just about anything? check. Doing DSP stuff on a calculator is pretty cool.
Granted such things are not really necessary unless you are a student because there are computer programs and web apps that can out perform it. Having a calculus/algebra/differential equations/dsp/boolean logic portable device is undeniably neat... though I think the end of calculators is coming because of tablets which can perform all the functions with higher resolution/less cryptic programs.
I think the main problem with programmable calculators is the long learning curve, especially for user made programs. You have to read text files and remember commands, how to format stuff.. it would be much easier with a touchscreen gui.
Then again a calculator has the benefit of lasting a long time, being durable, having nice buttons. I would still prefer a ti89 tablet though. Though I suppose you might as well just run mathematica or maple on the tablet.
though I think the end of calculators is coming because of tablets which can perform all the functions with higher resolution/less cryptic programs.
One thing that all these tablets have in common is touch interface...which necessarily means that they all inherently lack one critical factor of the user experience: unique tactile feedback. As Johnny Lee has pointed out, we often neglect the probability of failure and its associated cost on the user experience when considering new glamorous technologies that popular consumer banter would suggest as a replacement for "the old way". Consider the damage caused by "iphone autocorrect". Now replace relatively harmless text messaging with calculating numbers; most people don't crunch numbers for a quick "lol".
P.S. I don't what it is about this presentation, but it never seems to get old.
I use my 50g
and feel very weird using a non rpn one (have a 48 and 49g+ too, 49g+ of course is broken... due the bad quality of this series)
I really like how the new TI looks (the one with color screen and li-on battery) and almost I buy one, hehe but I will keep my loyalty to hp ..... for now
I could understand the need for tactile feedback when you are crunching numbers doing accounting but running more complicated programs tends to be annoying... especially typing letters.
I could understand the need for tactile feedback when you are crunching numbers doing accounting but running more complicated programs tends to be annoying... especially typing letters.
As previously mentioned, one argument for why querty keypads are not as prevalent in calculators (as opposed to cell phones) is its reclassification from "calculator" to "computer". From a design perspective, firmware and a well thought out overlay would solve the typing letters problem, but the consequential impact on the majority target market (students and what tools are considered acceptable) would be adversely affected thanks to the established rules of play.
You'd have to clarify your definition of "complicated programs"; there's a very large gray area that encompasses what a device can do and what it ought to be used for. It goes without saying that with any design, a balanced compromise must be decided upon, and from a user perspective, I'm of the opinion that tactile feedback holds significantly greater weight than what popular consumer products have demoted it to...no doubt driven by the vogue of marketing forces. After all, a user may have to deal with "complicated programs" every once in a while, but interfacing is an any-time-the-device-is-picked-up affair.
I mostly use google calculator or matlab. Google calculator for its ability to do arithmetic on dimensioned quantities, and it is sufficient for 99% of cases where I would use anything resembling a hand-held calculator. I use matlab for plotting, or for doing more complicated math/programming.
I do have a calculator on my phone which I use as a last resort.
For hand held calculators I used to love my HP48GX, but I haven't used it in ages.
As another posted said, the scientific calculator is dying, if not already dead, IMHO. Its primary use in my observation, is education. VPAM, graphing etc., are mostly for novice users, which is currently the target market for calculators.
The key issue is after you make a calculation, what do you do with the result? Integrate it into another program for further processing? Enter the result in field, in a computer? So, for the most part, calculators today for professional use are mostly for back of envelope brainstorms, and quick approximations, rather than for precision work.
Even in the simplest use, debt or mortgage calculations, actual results by banks use very high precision numbers, 2-30x more than a general scientific calculator. However when sitting down with the bank agent, they are opt to use a calculator to give the customer a ballpark figure. Often a feature of a specific 'financial calculator' is they do have higher precision numbers compared to a general scientific or programmable one [ 16-32 bit numbers in financial, versus 10 or 11 digits in the Casio FX260] or present the amortization table on a PC their working with, again making the calculator superfluous.
So, in the end, the modern scientific calculator is more like the slide rule was before 1980, to make estimates, but instead of breaking out the log or trig tables and extending the precision, we punt it to computers instead.
RealCalc puts a scientific calculator on my Android phone, and I use it about as much as my FX260, but the cramped screen makes it less attractive to reach for. Its main appeal is it works very much like the FX260.
TI-89 Titanium. I wish I had gone for just the regular ti-83 looking back.
So, in the end, the modern scientific calculator is more like the slide rule was before 1980, to make estimates...
I hope you'll excuse me for raising an eyebrow when a NIST engineer speaks of numerical "estimates".
Even in the simplest use, debt or mortgage calculations, actual results by banks use very high precision numbers, 2-30x more than a general scientific calculator.
This is actually a myth propagated by financial types who don't understand math. Financial transactions are rounded to the nearest penny, and intermediate values in a financial calculation will be rounded aggressively at every step along the way. A double precision float has an effective 53 bit significand, more than enough dynamic range for financial calculations on any scale smaller than the GDP of a G8 country.
The problem is simply that (binary) floating point arithmetic of any precision is unsuitable for financial transactions because certain values are not representable. You can't represent $0.10 exactly in as floating point number. When written in base 2, the number 1/10 is an infinitely repeating fraction, so it can't be captured exactly with any finite width number.
The upshot of this is that if I transfer $0.10 to your bank account, and our balances are represented as floating point numbers, the total amount of money before and after the transaction is not constant. This is obviously bad!
So financial calculations must be done either with integers (representing cents), or decimal (BCD) representations. It isn't that the financial type necessarily has more resolution, it simply has the specific type of rounding behaviour required for financial transactions.