HP50g plotting question

[MikeO]

Hmm. When I attempt to plot y1(X)=ABS(SIN(X)), I get full sine curve in the plot display. I would expect all positive values from this function - and thus a series of "humps" in the positive Y, positive X area. The plot seems to ignore the ABS function.

Any ideas why?

Thanks,

MikeO

[MikeO]

Hmm. I turn on "rigorous" mode and it fixes the graph. I think that's the right answer.

Thanks,

MikeO

[Don Shepherd]

Hmmm. So "non-rigorous" = mathematically incorrect? That's bothersome.

[MikeO]

That's about the size of it! ;)

I thought it was strange as well. Perhaps there is some narrow domain/range in complex number functions, or certain algebras, where |X| should be considered X, but I'm not sure what they would be.

MikeO

Edited: 5 Sept 2008, 10:09 a.m.

[Hal Bitton in Boise]

I've gone the rounds with this a time or two myself. With rigorous de-selected, you can manually use the "ABS" function, but that's about it...ABS will not work programmatically or in an expression.

The manual says "The CAS can solve a larger variety of problems if the rigorous mode is not set.
However, the result, or the domain in which the result are applicable, might be
more limited."


Not sure why this is...perhaps one of our resident math guru's could shed some light on this.

Best regards, Hal

[MikeO]

Yes, I'd love to hear if someone has a good explanation of why this is a useful option.

I wish I had an "accept false premise" option on the calculator. Then I could prove any theorem with it. A powerful feature indeed!

MikeO

[Chotkeh Software Corporation]

On our site there is an example of plotting covered. You will find it under Quick Start. A simple solution, but it may help. We have a few free PDFs which may help you in the process of learning the 50G. Owner.

[hpnut]

Quote:

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On our site there is an example of plotting covered. You will find it under Quick Start. A simple solution, but it may help. We have a few free PDFs which may help you in the process of learning the 50G. Owner.

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Hello,

thanks for alerting me to your website. Under your "Functions" PDF, I learned that the SPC key also works like the ENTER key. I never knew that. sigh, if only HP had made one big SPC/ENTER key :-(

hpnut in Malaysia

Edited: 1 Oct 2008, 4:24 a.m.

[Chotkeh Software Corporation]

Well they are separate keys because at some points they also have there own functions.

[Chotkeh Software Corporation]

We will have another Free PDF File, which will be on our site within a week. It will cover the key functions of the device. You will find it under "About the HP 48GII, 50G, & 49G+ Graphing Calculators" Even though the devices user's manual covers this, we cover it a little further in detail.