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[Dwight Sturrock]

TI's littered the classroom (Advanced Math Methods in EET) as the professor droned on about imaginary numbers. HP42S in hand, I wondered why he had to make the subject so laborious. Later at home, I tried SQRT -1 on my Purdue recommended TI-83. In anguish, I wondered what will happen to me if my HP42s gives up the ghost...

[Don Shepherd]

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I wondered what will happen to me if my HP42s gives up the ghost...

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... and then I remembered what the prof told us about putting the 83 in a+bi mode...problem solved.

:)

[Dwight Sturrock]

For some reason he didn't mention that. I'll have to check that function on the TI. Thanks for the heads up :]

[Bart (UK)]

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....putting the 83 in a+bi mode...

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Modes, modes. Why does it have to be modes? This "modes" thing is what got me to get rid of my fx-850p 25 years ago (I had a 28C before that and a 28S after). I don't change modes when I need to work in complex, why should the calculator? When complex is required, it must just do it. I know when I am expecting complex answers and when not. I know to "rephrase the question" if the calculator gives a real answer when I'm looking for a complex one & vice versa. Although I am more into RPL machines, I respect the 42S and for the life of me can't understand why HP didn't continue that line of calculator (instead of the 33s & 35s which are based on the 32s).

Just my 2 pence worth. :)

[Don Shepherd]

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Why does it have to be modes?

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Bart, I don't know, I guess that's the way the designers designed them. I think most TI's work that way, including the NSpire. I guess it's easier to design them that way than the way you suggest.

Don

[Marcus von Cube, Germany]

If you look at the many RPL system flags you know that there are modes, too.

Casio has made significant changes to their graphing calculators concerning modes. In the early days (I own a fx-8000G) it was modes everywhere. The main key for influencing the behavior of the calculator or selecting an application (editor, base-n, stats) is even labeled "mode". With some later models (fx-7700GE to CFX-9800G), they switched to an icon menu and relabeled the mode key "menu". Internally, it was not too much of a difference but at least switching from degrees to radians became a menu selection. OK, the setup screen is now shift+menu which is not really far from its former "mode" selection. With the most recent line (including the Prizm) the menu selections behave much more like seperate applications and all internal behavior switching has been delegated to menu selections.

Back to complex numbers: The cube root of a negative value returns different results on RPL machines depending on complex mode or real mode. I just tried on my Nspire and got a similar result. You need a way to tell the function which result you desire (cube root has three). So to avoid modes, you need to supply additional functions or parameters. Modes act like global variables with all their pros and cons.

[Martin Pinckney]

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...I respect the 42S and for the life of me can't understand why HP didn't continue that line of calculator (instead of the 33s & 35s which are based on the 32s).

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Apparently most of the engineers on here can't understand that.

The business types say, it's simple: The 42s quit selling. And the 48 series was selling, and has continued to in the later incarnations, including today's flagship, 50g.

[Dwight Sturrock]

As long as my 42S gets me through the next 2 semesters, I'll be happy. Then I can get a 50G and figure out how that works. Hate to change midstream.

[Karl Schneider]

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Modes, modes. Why does it have to be modes? This "modes" thing is what got me to get rid of my fx-850p 25 years ago...

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Good point, Bart. Indeed, Casio has long been enamored of operating modes, and still makes extensive use of them in the cheap but capable fx-115 series.

Flag 8 on the HP-15C and CRES/RRES on the HP-42S are "modes" of a sort, as are many of the flags on the HP-41, HP-42S, and HP-48,-49,-50 models. The real issue is whether functionality is cohesive and complementary.

On Casio models, this is often not the case. To use one kind of functionality requires that a particular mode to be entered, which then disables the functionality that is accessed by another mode. It is as though the calc is intended to be used to help the user learn the scholastic 'topic du jour'.

By contrast, on the HP-15C -- to use one example -- all functionality is always available, as long as sufficient memory is allocated. Statistical functions, integration, rootfinding, complex-number calculations, and matrix calculations can all be programmed and used cohesively.

-- Karl

Edited: 12 Feb 2011, 3:01 a.m.

[Bart (UK)]

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The real issue is whether functionality is cohesive and complementary.

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Karl, you have hit the nail on the head there. That was basically my issue. I found that the HPs of the time did it the best.