Recommendations for RPN Calculators?

sg3000 asks: "My trusty old HP 48S graphing calculator, that served me since engineering school, seems to be giving up the ghost. I haven't used it in a few years, but recently I put new batteries in it. It works, but it makes a loud static/white noise sound when it's on. The noise is not as noticeable when I hold it, but when I set it down on a hard surface, it's really loud. Then it sucks the batteries down incredibly fast (I put new batteries in it, and two days later, they were drained). Any suggestions on what I should buy as a replacement?"

"I'm in graduate school now, and since I'm taking an accounting course, where they don't want us digging out our laptops during a test, I need to buy another calculator. I'm a big fan of reverse polish notation (RPN), so I'd prefer to get another HP calculator.

Do companies still make calculators? I'd love to get another HP 48, but I'm not even sure if HP even makes calculators like that any longer -- on their web site, they're all cheapo-looking single line deals. I've read about something called an HP 48g, but HP has nothing about it on their web site."

Comments

HP 48GX

[mr.henry]

Buy an HP 48GX. It's the last decent HP scientific calculator and the RPN works great. The new HP's (like the 49G+) are crap, and aren't even made by HP. (They're rebranded.)

Why does HP's current calculator lineup suck?

Re:HP 48GX

[dogberto]

I'll have to disagree with your statement that "TI just doesn't cut it." True, their low to mid range graphing calculators (e.g., 73, 85, etc.) can't compare to any of the HP's current (or past) graphing calculator offerings. However, the TI-92 PLUS and TI-89 can very much hold their own in comparison to the HP's.

My primary calculator is the TI-92 PLUS (I used to use a TI-85) and the HP 48 series can't beat the ease of the TI-92 PLUS in terms of entering/performing symbolic operations. What do I use it for? I use it to check that I haven't made a mistake in my pencil and paper grunge work (i.e., arithmetic or algebraic manipulation [my level of math is well beyond calculus so basic algebraic manipulations are considered somewhat grungy]).

The symbolic manipulation of Mathematica is vastly superior to that of the TI-92; however, it is inconceivable that I have ready access to my laptop or another public computer that has Mathematica on it. So, in those moments, I whip out my TI-92 to verify that I didn't make a silly error such as sign dropping or whatever in those calculations which require a page long worth of algebraic manipulation.

Re:HP 48GX

[BrokenHalo]

One way in which the TI-89 (and upwards) blows away my HP48G+ is in integration. The HP is so slow at definite integrals that it is actually quicker to get out a piece of paper and a pencil and do it the old way. The TI, however, spits out the answer almost instantaneously.

PDA?

[steveha]

Depending on how hard you work your calculator, you might do better to get a PDA and run a calculator program on it. If you bang on your calculator keys for hours, get a real calculator.

I use Palm PDAs (my current one is a Tungsten T) and I run a program called RPN on it. It's programmable and it has graphing, but I haven't used those features; but as a general-purpose RPN calculator, it's kept me happy.

What I really want is something similar to Palm RPN that is programmable in Python.

Anyway, the best thing about this is that I always have it with me. I used to have an HP calculator, but it was never handy when I wanted it.

steveha

Keypresses

[X-wes]

I agree that keypresses saved are minimal, if not sometimes nonexistant in simple equations. In fact, for many simple single-operation equations, the process of learning RPN is far too complicated to justify using it at all.

RPN, however, can be likened to the Dvorak keyboard layout. It is entails a slightly involving process to learn. For many purposes, this is simply a pain. The true power only shines in complicated equations, such as those which make use of brackets.

The following equation shall be typed on an algebraic calculator, followed by an RPN calculator. [;] will be the button name for [Enter].

25 ( 46 ) + 254 - 2462 / ( 645 - 2453 )

Algebraic:

25*46+254-2462/(645-2453);

RPN:

25;46*254+2462;645;2453-/-

In the above example, you will realise that the number of keypresses is exactly the same. (In fact, if you cheat and leave out the second bracket on the algebraic calculator, that calculator edges out the RPN by one keystroke!) However, there are three immediate benefits to the RPN calculator:

• Less keys to hunt down--only uses Enter and four operation keys
• Feedback at every step--shows current X register as it changes
• No need to override order of operations when necessary

Over time, the amount of keypresses will not really be changed too drastically. However, the true power is the convenience and the ease of use. Unfortunately, like the Dvorak keyboard, RPN will slowly fade in the non-specialised markets due to the fact that it takes too much time to learn.