HP49G



#13

I've developed a problem I haven't been able to figure out. I just got a used HP49G and am trying to learn its in and outs. When I first got it, everything worked as the manual said it should. I could enter any formula or calculation and I'd get the expected answer. Hovever, a few days ago, it started doing something different.

Now, anytime I enter Anything with an unknown in it, I get an error message: "ERROR: Undefined name"

At its simplest, if I put in 2 * 2 I get the answer - 4. But if I put in 2 * X, I get the error message.

I've tried resetting everything and clearing out all the memories but there's no change.

What am I doing wrong???


#14

Go to the modes menu and uncheck the approximate mode. Also, you can go the the flags list and uncheck flags 1,2, and 3.


#15

Thanks Michel, that did the trick. The approximate chioce and flag 3 were checked, although I can't imagine how either of them got that way. When I got the calculator I didn't have the problem. It only developed after I had it several days. Oh well, thanks again.

David


#16

Hi, David;

I was wondering about the weird setting without any attempt to set it and I thought that you may possibly had chosen Approximate in orther to perform any of the examples available in the manual so you could see the effect of this. If not you, maybe someone else that access your calculator without problems (do you have kids?).

It happen something like this to me from time to time. The last one was creating, in the root directory, a variable named 'X' (HP48G+).

What happens next? Anytime you key in X without quotes cause the variable X to be evaluated. Even if the calculator is positioned in a different directory... The OS serches for the X in all directories 'above' the one you are worling now, so any variable stored in the root directory echoes its contents in any other directory if its name is written without quotes.

Learning and learning evryday...

Cheers.

Luiz (Brazil)


#17

Luiz said:

Quote:
I was wondering about the weird setting without any attempt to set it and I thought that you may possibly had chosen Approximate in orther to perform any of the examples available in the manual
so you could see the effect of this. If not you, maybe someone else that access your calculator without problems (do you have kids?).

Aren't there some math operations that change the settings of the flags automatically? I know Erable does this with some of the flags, and the 49G software is based partly on Erable. It's possible that David performed some operation that changed the flags without his knowledge. However, I don't remember if the "Approximate" flag is one of the flags that changes automatically or not.


#18

Thinking about it and the above responses makes me think that I must have created the problem by following the examples in the manual. I started on page one and more or less just went through the whole thing one page at a time, trying everything there.

BTW, re: the manual - it's just an average guide, at best. As a teaching tool, it sucks. Is there a comprehensive book available? I've been able to deduce several things not specifically shown in the manual but I have to think I'm missing a lot, given the obvious capabilities of the machine.

David


#19

David

I seem to recall some examples that set the approximate mode. It may have been one of the numerical integration examples or perhaps one of the root finding examples.

I agree that the manual is bad. If you can get your hands on the manuals for the HP48GX (I have a 48GX and all its manuals, and prefer using it to the 49G for most things), you will find that most (obviously not all) of the information for operating the 49G is available in the 48G manuals. What will be missing will be the stuff on CAS. With CAS you have to be aware of the additional types of objects and how they are handled by the 49G. The manuals for the 49G+ would also have much that applies to the 49G. I was able to download these from one of the HP afficionados websites, but at the moment I can't remember which one. I'll try to get the info and get back to you.

Mike

#20

I'm back already. Actually you can get CD's from this website. Follow the links to Other Calculators and the 48 series. You will find links to how to get the CD's.

The other website is www.hpcalc.org. There are all kinds of things there.

Mike


#21

Oh, and DUH!, http://www.hp.com/calculators/ click on the 49G+ and look for product manuals. They are both there.

Mike


#22

Thanks Michael

I've now downloaded and printed several humdred (!!!) pages here. I've found a couple of other sites that have enough other information to keep me busy for the rest of the winter.

David

#23

Hi Wayne, folks;

I read your post again and I'd like to know one thing: was Erable originally writen for the HP48G? If so you're right, i.e., the "approximate" flag was surely not changed because the HP48G has no such definition, right?

Just to add this.

Cheers.

Luiz (Brazil)


#24

You're right, Erable was written for the HP48. It uses some of the user flags for keeping track of various settings that determine Erable's behavior. I don't know whether it uses one as an "approximate" flag or not, but it does operate in both an exact and an approximate mode, which can be set by the user and which sometimes switches automatically. Here's an excerpt from the Erable 3.2 documentation:


Quote:
Most of the time, you will use Erable in exact mode, where no approximations are made. But sometimes, exact solutions can not be computed on the HP48 (e.g. if you want to factor x5 + x + 1), and Erable will switch to the numeric approximation mode where e.g. SQR(2) is handled as 1.414235...

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