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Removing Calculus features from HP-15C
Message #1 Posted by skroops on 20 Nov 2008, 9:55 p.m.

Well I wanted to use my 50g for my upcoming math class, but they don't allow the use of calculators with calculus features or symbolic algebra. I still wanted RPN but so I started to look for a basic RPN calc. Somehow or another ended up looking enviously at a 15C picture, and realized it looked like a calculator my mom used to have. I called her up and it turns out she still has it, in good condition with a dead battery.

So anyways, I was thinking of how I could use it in my math course. Would it be possible to just remove the key for integration, and perhaps put some sort of material over the contact to protect it? Would this eliminate all calculus features from the calculator? The only other one I could think of was if I built a program to do integration, so I'd have to take the program key out as well, and clear the memory.

Any input?

Thanks

      
Re: Removing Calculus features from HP-15C
Message #2 Posted by Chuck on 20 Nov 2008, 10:22 p.m.,
in response to message #1 by skroops

Don't ruin the 15c. Find an 11c to use instead.

            
Re: Removing Calculus features from HP-15C
Message #3 Posted by skroops on 21 Nov 2008, 11:05 a.m.,
in response to message #2 by Chuck

I don't want to ruin it, that's why I asked first ;)

      
Re: Removing Calculus features from HP-15C
Message #4 Posted by Jeff O. on 20 Nov 2008, 10:58 p.m.,
in response to message #1 by skroops

Are you certain that your math class will not allow the 15C? The calculus features are numerical only, it doesn't have any symbolic capabilities. To your question, the keys are not really "removable". You could go through an ugly process to eliminate the key, but then you would no longer be able to multiply since the the integrate function is the yellow-shifted function on the multiply key.

The 11C doesn't have a built in numerical integration function, I'm sure your could find someone to trade an 11C for your 15C. But of course an 11C could be programmed to perform numerical integration, so if that is not allowed you may be out of luck. The 10C is only barely programamble. I don't know if a numerical integration routine would be within its programming capabilities. But 10C's are quite hard to come by, so this is probably not a realistic option. If you need a cheap, easily available, non-programmable RPN calculator with scientific functions, the 20b might worth looking at. (Or maybe get an HP-35 or HP-45 if you want to be really retro, but then you would have to deal with rechargable batteries and no continuous memory.)

            
Re: Removing Calculus features from HP-15C
Message #5 Posted by skroops on 21 Nov 2008, 10:33 a.m.,
in response to message #4 by Jeff O.

Quote:
To your question, the keys are not really "removable". You could go through an ugly process to eliminate the key, but then you would no longer be able to multiply since the the integrate function is the yellow-shifted function on the multiply key

OK, that answers that. I don't want to ruin it, or eliminate multiplication ;). Thanks

Quote:
I'm sure your could find someone to trade an 11C for your 15C.
I think that'd be a bit of a one-sided deal ;) Let me guess, you just happen to have an 11C you'd be willing to offer? (just kidding)

Quote:
If you need a cheap, easily available, non-programmable RPN calculator with scientific functions, the 20b might worth looking at. (Or maybe get an HP-35 or HP-45 if you want to be really retro, but then you would have to deal with rechargable batteries and no continuous memory.)
Ooh... that HP35 is a little too retro for my taste. The 20b is SEXY however. I could do without the accounting keys but it's still pretty.

Edited: 21 Nov 2008, 11:03 a.m.

      
Re: Removing Calculus features from HP-15C
Message #6 Posted by DaveJ on 20 Nov 2008, 11:22 p.m.,
in response to message #1 by skroops

The 15C is worth a LOT on eBay
It would be foolish to modify it in any way. Sell it and get a cheaper beat-up 11C instead.

Dave.

      
Re: Removing Calculus features from HP-15C
Message #7 Posted by Les Wright on 21 Nov 2008, 12:58 a.m.,
in response to message #1 by skroops

I can't imagine that any sensible calculus course would ban the 15C because of its numerical integration capacity. The feature is fun, but slow by today's standards and really not of any assistance with the symbolic and exact problems on a traditional undergraduate calculus text.

When I studied undergraduate calculus calculators were neither permitted nor necessary. In physics and chemistry when numerical approximations to analytic results were required, certainly. But definitely not in calculus.

            
Re: Removing Calculus features from HP-15C
Message #8 Posted by skroops on 21 Nov 2008, 10:53 a.m.,
in response to message #7 by Les Wright

Yes, I wouldn't think so either, but the math and science departments at this university tend to be overly-cautious and a bit anal-retentive. I hope your right about it not being of any assistance. I don't really know enough about the calculator or the math course to see if it would violate their policy. I could ask, but I don't want to volunteer the information that I think it may violate their policy, as I think that would make it more likey that they would reject it. Here's what the actualy policy says:

Quote:
Calculators are permitted (but not required - see below) during exams, except those calculators that have symbolic algebra or calculus capabilities. In particular, the following calculators and their upgrades, are not permitted: TI-89 TI-92 TI Voyage 200 HP-48 HP-49 Casio FX2.0 Casio CFX 9970G In addition, neither PDAs, laptops nor cell phones are permitted. Violations of this policy will be referred to the Committee on Academic Misconduct.

There are at least two reasons for this policy:

It is unfair to students who can't afford to buy such calculators. Proper use of such calculators requires extensive training, which we cannot provide due to time and other constraints. Exam problems are written so as not to require any calculators and you can leave your answers as expressions such as

instead of 24.64134. Conversely numerical answers from a calculator without any justification will receive no credit. On the other hand intelligent use of calculators may be helpful for checking your answers.


I especially like the "other students can't afford it" line, considering they basically force you to buy both Windows and MS Office, together at least $200 more than my 50g :\

Nevertheless, would you still think it wouldn't be a problem after reading that?

Edited: 21 Nov 2008, 11:08 a.m. after one or more responses were posted

                  
Re: Removing Calculus features from HP-15C
Message #9 Posted by Marcus von Cube, Germany on 21 Nov 2008, 11:51 a.m.,
in response to message #8 by skroops

I'm pretty sure you can use your 15C. Since it has no symbolic capabilities at all, just numerical approximations for solve and integral, it will not be banned.

                  
Re: Removing Calculus features from HP-15C
Message #10 Posted by Chuck on 21 Nov 2008, 1:03 p.m.,
in response to message #8 by skroops

By their explanation and reasoning, I'd say the 15c wold be allowed, and in most cases would only be useful to numerically check your answer.

                  
Re: Removing Calculus features from HP-15C
Message #11 Posted by Hal Bitton in Boise on 21 Nov 2008, 8:04 p.m.,
in response to message #8 by skroops

Quote:
Calculators are permitted (but not required - see below) during exams, except those calculators that have symbolic algebra or calculus capabilities. In particular, the following calculators and their upgrades, are not permitted: TI-89 TI-92 TI Voyage 200 HP-48 HP-49 Casio FX2.0 Casio CFX 9970G In addition, neither PDAs, laptops nor cell phones are permitted. Violations of this policy will be referred to the Committee on Academic Misconduct.

You could use a 15C in the class, as clearly stated by the above regulation. Keep a copy of the reg with you in case any faculty gives you trouble. It's funny...all of the banned machines above can be had for much less cost than a 15C (with the possible exeption of a 48gx black LCD).
Best regards, Hal

      
Re: Removing Calculus features from HP-15C
Message #12 Posted by George Bailey (Bedford Falls) on 21 Nov 2008, 2:09 a.m.,
in response to message #1 by skroops

Ask your teacher/professor, show him/her the 15C, make sure he/she gives it back ;-) and don't EVER do any DIY/Mythbusters/MacGyver job on it! Never! NEVER!

      
Use a slide rule!!!
Message #13 Posted by Namir on 21 Nov 2008, 6:01 a.m.,
in response to message #1 by skroops

I recommend the good old slide rule. You are very safe from having no calculus features incorporated in the slide rule. You spare yourself the headache of selecting a calculator. You also spare an HP-15C from being mutilated.

You can easily buy a slide from eBay.

Namir

Edited: 21 Nov 2008, 6:03 a.m.

            
Re: Use a slide rule!!!
Message #14 Posted by Walter B on 21 Nov 2008, 6:16 a.m.,
in response to message #13 by Namir

Quote:
You can easily buy a slide from eBay
... or many (!) slide rules for the price of a 15C.
            
Re: Use a slide rule!!!
Message #15 Posted by skroops on 21 Nov 2008, 11:11 a.m.,
in response to message #13 by Namir

I think that's funny; but honestly I don't even know what a slide rule looks like, let alone how to use one!

                  
Re: Use a slide rule!!!
Message #16 Posted by George Bailey (Bedford Falls) on 21 Nov 2008, 12:03 p.m.,
in response to message #15 by skroops

Quote:
I think that's funny; but honestly I don't even know what a slide rule looks like, let alone how to use one!


Have a look here for a virtual one and here for instructions. Even in the age of CAS calculators they can be very handy. At least the tiny ones...

Edited: 21 Nov 2008, 12:03 p.m.

                  
Re: Use a slide rule!!!
Message #17 Posted by Namir on 21 Nov 2008, 12:23 p.m.,
in response to message #15 by skroops

Thanks ... I meant to inject som humor. The post above me shows you online slide rules. They are cool and easy to use.

A slide rule is an analog device since it is repeat the solution you seek (if one wants to be fundamental). Just trying to make the slide rule sound a bit more important that it is.

Namir

                        
Re: Use a slide rule!!!
Message #18 Posted by Chuck on 21 Nov 2008, 7:29 p.m.,
in response to message #17 by Namir

Last week I took my 7-foot Pickett instructor slide rule into my Precalc class and discussed the 380 year history of it, it's eventual demise due to the HP35 in 1972, and several types of calculations. I first showed the students how to add numbers using meter sticks as the the foundation of slip-sticks; then proceded on to how multiplication works, and then on to exponential expressions (we had just finished the chapter on logarithms.) They finally realized what the log-log of a number was useful for.

We also had a good discussion about the N600 (which I took to class) that went to the moon, and the part of the movie "Apollo 13" that shows the brainiacs at the space center feverishly calculating with the slide rule.

Several students stopped by my office to see the slide rules again. I need to try and find a cheap set of about 30 slide rules to give them some actual hands-on math-history practice next time.

They were most impressed about the need to estimate the magnitude of the results, ie., is the answer 0.0000354, 3.54, or 35400000? Estimation skills are something that is truely lacking in today's students (I think due to the rampant use of calculators.)

Anyway, knowing how a slide rule works is not a bad thing.

                              
Re: Use a slide rule!!!
Message #19 Posted by Chad Wermager on 21 Nov 2008, 7:42 p.m.,
in response to message #18 by Chuck

I think it's great that you introduced the slide rule to your class. I have never even seen one let alone know how they work (throughout high school and 3 semesters of calculus). I was actually talking with an engineering professor the other day about how the fundamentals have have been lost with new students (I am a non-traditional student in the fact that I am getting a second bachelors). A simple calculus problem deriving a centroid on our last exam was a disaster for the majority of the class and many can't even solve simple linear simultaneous equations. His theory is that students are too reliant on calculators these days and I agree. Calculators are fascinating devices, but how much are we sacrificing by relying on them for everything?

                              
Re: Use a slide rule!!!
Message #20 Posted by Steve Perkins on 21 Nov 2008, 8:09 p.m.,
in response to message #18 by Chuck

After reading some comments about slide rules on this forum recently I went looking on that auction site for them.

Big mistake! You would think I've spent enough on calculators! My wife surely does. I have aquired a few and more are on the way.

I learned to use them in high school, but had to teach myself by reading books from the library. Very interesting in my opinion. I'm glad you're teaching your class about them, it gives a wonderful perspective.

                              
Re: Use a slide rule!!!
Message #21 Posted by Garth Wilson on 21 Nov 2008, 11:41 p.m.,
in response to message #18 by Chuck

Quote:
and discussed the 380 year history of it, it's [sic] eventual demise due to the HP35 in 1972
I would say its demise did not come quite that soon, because calculators were initially much, much more expensive, and not particularly any faster if you were proficient at the slide rule. Even after all my peers were using calculators in school, I kept using the slide rule until I needed something programmable. As a result, I think I understood number relations better. Even now, a co-worker marvels at how easily I convert decibels in my head. I tell him it came from using the slide rule. The others in my high-school physics class didn't think slide rules could possibly be very accurate, but they were impressed when my answer for the time required for a satelite to orbit the earth at a certain altitude was only four seconds different from the teacher's answer from his calculator. Today I pull a slide rule out for calculations a couple of times a year just for the heck of it. My smallest one takes about as much room in a shirt pocket as a couple of pens.
                              
Re: Use a slide rule!!!
Message #22 Posted by George Bailey (Bedford Falls) on 23 Nov 2008, 9:57 a.m.,
in response to message #18 by Chuck

Quote:
I need to try and find a cheap set of about 30 slide rules to give them some actual hands-on math-history practice next time.

Have a look here. They have a Loaner Program.

                                    
Re: Use a slide rule!!!
Message #23 Posted by Palmer O. Hanson, Jr. on 23 Nov 2008, 10:25 p.m.,
in response to message #22 by George Bailey (Bedford Falls)

Quote:
Have a look here. They have a Loaner Program.

But, you might want to be careful about which set you ask for. Sets 2, 6, and 7 offer slide rules with the so-called Darmstadt configuration where the trigonometric scales are on the frame rather than on the slider. That means that there are some relatively straightforward calculations which become more complex than with the Mannheim configuration.

Palmer

      
Re: Removing Calculus features from HP-15C
Message #24 Posted by bill platt on 21 Nov 2008, 8:36 a.m.,
in response to message #1 by skroops

Go ahead and trash your 15c. It will only make mine more valuable.

            
Re: Removing Calculus features from HP-15C
Message #25 Posted by skroops on 21 Nov 2008, 11:10 a.m.,
in response to message #24 by bill platt

Okie-dokie


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