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Recommendations for RPN Calculators?

Posted by Cliff on from the still-better-than-an-abacus dept.

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."

9 of 580 comments (clear)

  1. HP 48GX by mr.henry · · Score: 4, Interesting
    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?

    1. Re:HP 48GX by dogberto · · Score: 5, Interesting

      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.

    2. Re:HP 48GX by Henry+V+.009 · · Score: 3, Interesting

      I know what you are talking about, and I agree that the TI beats HP in symbolic computation. I have known people who use it for just what you do, and they're pretty good with it. But for me, I am far more likely to make the errors when I am entering the equation into the machine. That is probably from lack of use, but I still prefer to do my own algebra and do the basic checks at the end. I am very fast with the HP when it comes to actually crunching the numbers at the end if necessary.

      Mathematica is an amazing program, and I have loved using it whenever I have come into contact with it. But I usually find that its symbolic capabilities are only useful for problems that I should be able to do myself. When I need numeric answers, it is usually MATLAB, or more often C++ armed with Boost and Blitz.

    3. Re:HP 48GX by BrokenHalo · · Score: 4, Interesting

      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.

  2. PDA? by steveha · · Score: 4, Interesting

    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

    --
    lf(1): it's like ls(1) but sorts filenames by extension, tersely
  3. Re:Brief HP calculator guide by Noehre · · Score: 3, Interesting

    The same team that made the 48 worked on the 49.

    The only 'problem' with the 49 is the soft non-clicky keys.

    Although, it has the added benefit of not being piss slow and has a (thank God) hard case.

  4. Keypresses by X-wes · · Score: 5, Interesting

    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.

    1. Re:Keypresses by Urkki · · Score: 3, Interesting

      The problem with RPN is, I imagine, that it's different. Normal algebraic notation is what everybody learns first before they get such calculator, and their thinking ends up following that notation.

      Picking up different notation is easy, but to "convert" your thinking between two different thinking models is much harder and takes longer time.

      Mind you, I don't know RPN, but I imagine that at first when learning it, you think of the calculation in a normal way and then covert that to RPN for the calculator, and it'll take time to learn to think of the calculation in RPN.

    2. Re:Keypresses by AKnightCowboy · · Score: 3, Interesting
      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.

      You can take my HP48GX when you pry it from my cold dead hands. The main advantage of the HP48GX and RPN in general is that I've never had it borrowed in a class by another student for more than 10 seconds. Meanwhile I can watch with a bemused look as they try to figure it out. Then they give it back and grab someone else's lame TI.