Need for paper & pencil with 48/49/50 calculators

[carey]

I'd like to discuss the extent to which 48/49/50 calculators eliminate the need for paper and pencil in multi-step problem-solving.

In the old but excellent HP video, Learning About the HP 48, William C. Wickes and Nathan Meyers show how, via chaining calculations and using symbolic equation manipulation, the HP 48 reduces the need to use pen and paper in problem-solving.

My questions are whether you think there's a sweet spot for the amount of pen and paper to use in multi-step problem-solving using 48/49/50 calculators or if you find you're able to dispense entirely with pen and paper? My impression, for now :), is dispensing with paper and pencil is doable, though not always desirable, unless a complete calculation history is available.

[John Garza (3665)]

If you could provide a little more context... types of problems, etc?


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Over a decade earlier HP was claiming the same with RPN. Sadly, it didn't go over so well with the masses as they were coming from a slide rule where you were constantly writing down intermediate answers. They viewed a calculator as only a slide rule replacement, not a complete problem solver. So the added cost of using an RPN machine wasn't worth it to many.

Sort of like the Betamax vs. VHS video tape formats back then. Beta was better, but not enough to justify the extra cost.

-J

[carey]

John, thanks for your reply!

Sure about additional context. I'm mainly interested in physics applications where, for example, starting with a conservation law and a geometric constraint, a model is derived and numerical values are introduced at the last step. Therefore, algebraic manipulations would be used more frequently than chained calculations. Here's an example: deriving the equation for a conical pendulum (rather than starting with the equation) and then substituting numerical values. It's interesting that Dr. Wickes was a physics professor before being recruited by HP and it wouldn't be surprising if the physics perspective of solving problems as generally as possible may have (positively) influenced some 48 series design decisions.

That's a great point you make about similar previous claims for RPN calculators in reducing paper and pencil use. Pioneer series solvers that solve for any unknown in an equation reduce the need for paper and pencil to rearrange equations (though, of course, don't have symbolic features to simplify or expand equations).

[john gustaf stebbins]

With the 48/49/50 I did find that most problems I worked with those machines could be done sans paper and pencil. Not that I never used paper and pencil. I would use the file system to create folders for each problem or class of problems I worked on. I could then save intermediate results and other information in the folder and switch between projects or problems by switching folders.

This is what I miss most using the Prime. Having only a limited number of variables and only one set of them means I need to clear out the calculator for each problem I work on. They have implemented a save feature, which would probably help, though I've not been able to make it work for me as yet. Any problem that is amenable to programming gives much more flexibility with the Prime, but it is not as flexible for problem solving as the 48/49/50 system. The Prime is really more a successor to the 38/40 machines which had similar limitations which are selling points in the educational market.

[carey]

John G.S., thanks for the suggestion to set up a folder for each calculation project to reduce or eliminate paper and pencil use!

Folder use is also helpful when writing RPL programs as a chain of short sub-programs since it minimizes stack manipulations as described in D. R. Mackenroth's book HP 48 Programming Examples.

[ttw]

The main thing I found was that I could do bigger computations than with pencil and paper. The CAS helped. One of the latest examples is that I can find a large (about 2 ^60) Sophie Germaine prime with a second number so that A/P has small partial quotients as a continued fraction. It takes a couple of minutes on the HP50g; and a few seconds on EMU48 on an S22U phone.

I like to go through a simple example of all my big math programs on a calculator (not by hand anymore). It helps avoid bad side paths when programming.

[nickapos]

(03-12-2024 12:13 AM)john gustaf stebbins Wrote:  With the 48/49/50 I did find that most problems I worked with those machines could be done sans paper and pencil. Not that I never used paper and pencil. I would use the file system to create folders for each problem or class of problems I worked on. I could then save intermediate results and other information in the folder and switch between projects or problems by switching folders.

This is what I miss most using the Prime. Having only a limited number of variables and only one set of them means I need to clear out the calculator for each problem I work on. They have implemented a save feature, which would probably help, though I've not been able to make it work for me as yet. Any problem that is amenable to programming gives much more flexibility with the Prime, but it is not as flexible for problem solving as the 48/49/50 system. The Prime is really more a successor to the 38/40 machines which had similar limitations which are selling points in the educational market.

Why do you say that prime has a limited set of variables? You can create as many as you want

[john gustaf stebbins]

(03-12-2024 03:51 AM)nickapos Wrote:  Why do you say that prime has a limited set of variables? You can create as many as you want

Yes, you can define other variables, but not in the middle of an expression. This actually leads to inconsistent behavior. Certainly not the flexibility of the 48/49/50 series.

The Prime is deliberately limited for specific market reasons. These decisions have been explained by the developers and make sense with what HP was trying to do with the Prime. It is not the calculator I want, but I'm not the target market.