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HP Forum Archive 21

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Who uses a graphing calculator, and for what?
Message #1 Posted by Peter Murphy (Livermore) on 19 Apr 2012, 11:53 a.m.

What day-to-day, practical applications does the graphing feature have? Why, that is, would one buy a graphing calculator without being required to do so in connection with course work? Or does one buy the HP 50g, for example, and pretty much ignore the graphing feature?

      
Re: Who uses a graphing calculator, and for what?
Message #2 Posted by Andrés C. Rodríguez (Argentina) on 19 Apr 2012, 11:59 a.m.,
in response to message #1 by Peter Murphy (Livermore)

HP-48G+ just for Minesweeper, Free42 for every other use.

      
Re: Who uses a graphing calculator, and for what?
Message #3 Posted by hpnut on 19 Apr 2012, 12:49 p.m.,
in response to message #1 by Peter Murphy (Livermore)

I love using my Hp 50g, just using the graphing features against math textbook problems, not in the course of my work.

      
Re: Who uses a graphing calculator, and for what?
Message #4 Posted by bill platt on 19 Apr 2012, 1:40 p.m.,
in response to message #1 by Peter Murphy (Livermore)

The 48G Champagne series are, while large, nevertheless superbe calculators. I haven't tried a 50G but I hear that for a contemporary machine, it is all that the 48G is and more.

If you want RPL, unlimited working restrictions and solvers, and the ability to handle both algebraic objects and reverse polish computation, there is no substitute for the 48,49 or 50. Of course we don't always need that. But I keep a 48 in my standard rotation.

      
Re: Who uses a graphing calculator, and for what?
Message #5 Posted by Crawl on 19 Apr 2012, 2:13 p.m.,
in response to message #1 by Peter Murphy (Livermore)

I have a feeling you don't know what use a graphing calculator has now. It's not just for graphing. But even if it was, it's much faster to set up a graph of a function (maybe not of experimental data) in a graphing calculator than it is in Excel.

Here's an example of when I used a graphing calculator for work when Excel faltered.

I had experimental values for the real and imaginary dielectric constant of a material as a function of wavelength and wanted to make a spreadsheet of its predicted transmission and reflection from that data.

This is possible, but the equations are preposterously complex.

Nevertheless, I dutifully typed them in.

I did some sort of common sense sanity check of the spreadsheet, I can't remember what it was, but it wasn't working out. It just did not work. I looked over the equations but couldn't find a mistake (of course, they were extremely complicated).

So what I did was I loaded the data into my HP50, in CSV format, using an SD card. I derived the equations from first principles, using the 50g's CAS. It is almost impossible to make a mistake this way. The starting point for the derivation is not very complicated, particularly if you can use complex numbers (which the HP50g can, easily, but which Excel handles very awkwardly), so it's easy to key in. Then I ran the calculation, put it back in CSV format, back on the card, and loaded it back into Excel.

I was eventually able to find that I had indeed made some typos in the original Excel file, by comparing data to the calculator output.

I can imagine all sorts of criticism of this. "Why didn't you use another program on the computer?" Blah blah blah. Doing it the way I did was relatively cheap (even if I hadn't already owned the calculator), and was quick, easy, bullet proof and just about guaranteed to work, and, you know what, it was even fun, too.

There are definitely uses for graphing calculators today (though I prefer to think of them as CAS calculators -- I'll admit I have little use for, say, a TI83).

      
Re: Who uses a graphing calculator, and for what?
Message #6 Posted by Dominic Richens on 19 Apr 2012, 3:25 p.m.,
in response to message #1 by Peter Murphy (Livermore)

I don't use my HP48SX very often and almost never for graphing. I do use it for solving equations, systems of linear equations and for symbolic integration. Lately I've been using Wolfram's web site for that stuff.

For day to day stuff it's the WP34s.

      
Re: Who uses a graphing calculator, and for what?
Message #7 Posted by Nigel J Dowrick on 19 Apr 2012, 3:36 p.m.,
in response to message #1 by Peter Murphy (Livermore)

I'm a secondary school Physics teacher. I often use a graphing calculator for plotting experimental results, either mine or the students'. I can tell quickly what the graph should look like and whether the experiment has behaved as expected, and I can do all this whilst walking around and answering other questions. A spreadsheet on a computer just isn't as convenient.

I really loved using my Psion 3a for this, many years ago now, but the hinges on those things don't last forever ...

Nigel (UK)

            
Re: Who uses a graphing calculator, and for what?
Message #8 Posted by Peter Murphy (Livermore) on 20 Apr 2012, 8:48 p.m.,
in response to message #7 by Nigel J Dowrick

Nigel, this is a nice use of the graphing function. What are some experiments in which you find it useful?

                  
Re: Who uses a graphing calculator, and for what?
Message #9 Posted by Nigel J Dowrick on 22 Apr 2012, 1:36 p.m.,
in response to message #8 by Peter Murphy (Livermore)

Just to be clear: it's me using the graphing calculator, not my students! At my school, essentially everyone has a Casio FX-83 or a closely related machine. (Many years ago, one student had a Casio FX-602P, and she gave me a Casio FX-603P as a leaving present. But I digress...)

Let's suppose we've done a class experiment - the time for a ball bearing to fall a set of distances, for example. Students need to plot a graph of this, by hand. (Their ability to plot points accurately is tested in examinations, so this isn't just me being old-fashioned!) Since I don't cheat, I don't know for certain in advance what the graph should look like. I use a graphing calculator to plot the points - it's extremely quick, and I can wander around the class while I'm doing it. If two students are arguing fiercely about whose graph is correct, I can settle the dispute quickly! If a student is having real problems, letting them see what the graph should be like can help them.

I could use a spreadsheet on the whiteboard (and sometimes I do exactly this) but often it's nice to let the students figure it out for themselves rather than showing them all what the answer should be. A graphing calculator keeps me one step ahead of the class when doing work like this.

            
Re: Who uses a graphing calculator, and for what?
Message #10 Posted by Marcus von Cube, Germany on 21 Apr 2012, 7:42 a.m.,
in response to message #7 by Nigel J Dowrick

I own several CBLs (TI, Vernier & Casio) with a few sensors. These devices are portable measurement units which connect to a graphing calculator. Here, the possibility to visualize the results of any measurements is essential. I'm doing it for fun only but a physics teacher will certainly have an application in his lessons.

If you can get hold of one (HP has the "StreamSmart" for this), do it! It's fun! :-)

                  
Re: Who uses a graphing calculator, and for what?
Message #11 Posted by Nigel J Dowrick on 22 Apr 2012, 1:42 p.m.,
in response to message #10 by Marcus von Cube, Germany

We have the Vernier machines in our science department. They work well. I also like iButton temperature recorders (you can bury these outdoors over the winter) and the scope and logger products from picotech.com. Playing with lots of cool stuff is a real perk of the job!

Nigel (UK)

      
Re: Who uses a graphing calculator, and for what?
Message #12 Posted by Dwight Sturrock on 19 Apr 2012, 11:47 p.m.,
in response to message #1 by Peter Murphy (Livermore)

The screen has to be big to support graphing. This gives us lots of space for the stack, which is what I find very useful.

            
Re: Who uses a graphing calculator, and for what?
Message #13 Posted by Cristian Arezzini on 20 Apr 2012, 11:40 a.m.,
in response to message #12 by Dwight Sturrock

This! The unlimited stack, with seven levels on-screen, is incredibly useful (or convenient) to me. Anything else is just a compromise. I use the 50g almost daily, but I almost never use the graphing functions...

                  
Re: Who uses a graphing calculator, and for what?
Message #14 Posted by aurelio on 21 Apr 2012, 11:37 a.m.,
in response to message #13 by Cristian Arezzini

Me too, for the same reasons!

Edited: 21 Apr 2012, 11:38 a.m.

      
Re: Who uses a graphing calculator, and for what?
Message #15 Posted by db (martinez, ca.) on 20 Apr 2012, 1:33 a.m.,
in response to message #1 by Peter Murphy (Livermore)

Nothing right now but i have ran both D'Zign and TDS surveying software on the 48sx i bought in 1991. Ted didn't use the graphing because it is slow but he got a lot of mileage out of the 8 line screen. TDS did a bit of screen plotting but it is slow and in the sun or with a dirty screen i wasn't all that useful. They did however fill every line of that big window every time with prompts and/or output.

So for me: just running canned programs.

            
Re: Who uses a graphing calculator, and for what?
Message #16 Posted by Iqbal on 20 Apr 2012, 10:44 a.m.,
in response to message #15 by db (martinez, ca.)

Surveying. The screen is large enough to show all the results. I wrote my own programs with a little help from friends like Luiz. One of my programs plot the parcel of land. The plot function is slow on the 48G+, but I can turn it off or on. On the other hand the 50G is very fast, and you see no difference in speed if the plot mode is on or off. I do have a speed up 48 and the plot function is pretty fast, but that is not for field use. It would have been great though if the 50G was rugged as the 48.

Edited: 20 Apr 2012, 11:48 a.m.

                  
Re: Who uses a graphing calculator, and for what?
Message #17 Posted by Peter Murphy (Livermore) on 20 Apr 2012, 10:13 p.m.,
in response to message #16 by Iqbal

Iqbal, I know that use of the 48G in surveying is important, but my knowledge of the subject is limited to what I see in my father's 1925 edition of Elementary Surveying, by Breed and Hosmer.

Do surveyors in general want to be able to plot parcels in the field? Do any of the surveying packages allow them to do this, or did you write your program in the absence of commercial software that does it?

                        
Re: Who uses a graphing calculator, and for what?
Message #18 Posted by Iqbal on 20 Apr 2012, 10:57 p.m.,
in response to message #17 by Peter Murphy (Livermore)

Hi Peter, I wrote my own programs to plot the traverse on the screen. Many commercial programs have that feature. Geocalc, TDS and D'Zign are a few, but I input the length and bearing and it would plot the traverse if I need it. I wrote the programs to suit how we work in Trinidad (and Tobago). Actually, I had some help on the plot feature from a guy name Jason Look, who is fantastic. Not that we would want to plot a parcel on the field, but it gives an idea of the shape, and once I plotted the traverse on the field and determined that the plan bearing wasn't 3 degrees but 13 degrees.

      
Re: Who uses a graphing calculator, and for what?
Message #19 Posted by Matt Agajanian on 20 Apr 2012, 12:05 p.m.,
in response to message #1 by Peter Murphy (Livermore)

Me! Me! As a calculator enthusiast, collector and mathematician, a graphing calculator represents quite a new set of operating system, number and graphical manipulation languages and techniques to learn and understand.

As I started my mathematical endeavors since I was six, I've always been interested in calculators. I'll admit, when I got my first programmable calculator, I got an SR-56 (yes, that one). Although I've also had the 58C that followed, my first HP was a 32E after I taught myself RPN. Ever since then, RPN-based HP's have regularly been added to my calculating toolkit.

The HP-28C was my first graphing calc. Then came the 28S and then the 48SX then GX. And, since I rather benefited from the 48GX's expansion card functionality, currently I have the 50G since it too offers expansion & card-based storage capability. Mainly, I chose the 50G for its SD card expandability. My purposing and using graphing calculators furthers that exploration and understanding as well as fascination with mathematics.

Now, from a programming perspective, graphing calculators represent the next level of either RPN, namely RPL and to understand the 'other guys' lingo for their TI-86 & TI-89 models.

Edited: 20 Apr 2012, 12:14 p.m.

            
Re: Who uses a graphing calculator, and for what?
Message #20 Posted by Gerson W. Barbosa on 20 Apr 2012, 10:27 p.m.,
in response to message #19 by Matt Agajanian

There was a time mathematicians used no calculators, graphing or not, but they allowed themselves up to one year to solve a problem:-)

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv018.cgi?read=145904

      
Re: Who uses a graphing calculator, and for what?
Message #21 Posted by David Hayden on 21 Apr 2012, 7:40 a.m.,
in response to message #1 by Peter Murphy (Livermore)

I rarely use the graphing feature, but I consider the large display to be a big asset. It's nice to see several levels of the stack, and thank goodness for input forms. It's also very handy when writing small programs.

            
Re: Who uses a graphing calculator, and for what?
Message #22 Posted by Garth Wilson on 21 Apr 2012, 9:43 p.m.,
in response to message #21 by David Hayden

I would think that's the greatest benefit. I have no use for the graphing myself, as I can visualize what the graph looks like unless it needs more resolution than a graphic calculator has, and I can visualize what's on the stack too, so I don't need to see that in the display. But when I write HP-41 programs, I like to use a text editor first on the PC and put in my comments and make it kind of structured, using the big screen, and then I enter it into the 41.

      
Re: Who uses a graphing calculator, and for what?
Message #23 Posted by Bart (UK) on 21 Apr 2012, 11:53 a.m.,
in response to message #1 by Peter Murphy (Livermore)

I use the 50g, but admittedly not very often for graphing. I like the big screen and have some programs for work with input forms.

      
Re: Who uses a graphing calculator, and for what?
Message #24 Posted by Tommy on 22 Apr 2012, 9:21 a.m.,
in response to message #1 by Peter Murphy (Livermore)

Not me. I use GeoGebra www.geogebra.org or Excel

      
Re: Who uses a graphing calculator, and for what?
Message #25 Posted by Eddie W. Shore on 23 Apr 2012, 8:52 a.m.,
in response to message #1 by Peter Murphy (Livermore)

I primarily using a graphing calculator to: (1) graph functions for illustration for my blog, (2) create interesting pictures using functions, polar equations, and parametric equations, (3) programming, and (4) using the CAS abilities to check my work.


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