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HP35s output displays (apologies, another question)
10-08-2014, 04:35 PM (This post was last modified: 10-08-2014 04:36 PM by Kyburo.)
Post: #1
HP35s output displays (apologies, another question)
Hi all,

Sorry to be a little spammy today in terms of queries!

I've mini uni math tests on each topic and I've had one just now asking for my output to be entered (into an online portal) in the form of an output including Pi - The question is the simplest we've actually had so far and so easy marks (It's actually a test to make sure people in first year understand their calculators!)

arcsin(1/2) = ?

the HP gives me back 0.5236.... but the only other option I've got is to convert it into a fraction which in this case isn't going to help me as they specifically want "Pi/6".

I'm sort of guessing that this is not a feature available in the HP35s? Which since I'm doing engineering I suppose isn't the worst thing in the world, but for my math classes (by the math department) they're most likely going to want this pretty often moving forwards.

Cheers!
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10-08-2014, 04:52 PM
Post: #2
RE: HP35s output displays (apologies, another question)
There's a nice 42S program that does that sort of thing, but converting it for the 35s would probably be tricky, with the lack of string-manipulation functions.

http://www.hpmuseum.org/software/qpi/42sqpi.htm
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10-08-2014, 07:21 PM
Post: #3
RE: HP35s output displays (apologies, another question)
(10-08-2014 04:35 PM)Kyburo Wrote:  arcsin(1/2) = ?

the HP gives me back 0.5236.... but the only other option I've got is to convert it into a fraction which in this case isn't going to help me as they specifically want "Pi/6".

I'm sort of guessing that this is not a feature available in the HP35s?

No, the 35s will not display 0,523598775598 as \(\pi/6\), just as it will not display 2,64575131106 as \(\sqrt{7}\) or 0,69314718056 as \(ln 2\). Simply because the 35s does not use some kind of CAS that could return symbolic results. Its answers are always numeric, rounded to 12 places.

On the other hand, if you really want to know which fraction of \(\pi\) the result stands for: a simple [\(\pi\)] [X<>Y] [\(\div\)] does the trick. And finally: do I really ask for too much if I expect students at university (!) to know that \(arcsin \frac{1}{2}\) is 30 degress or \(\pi/6\) and 0,5236 is the numeric value of this, and 1,5708 is recognized as \(\pi/2\) or 1,0472 as \(\pi/3\) ?-)

Dieter
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10-09-2014, 01:05 AM (This post was last modified: 10-09-2014 01:07 AM by Kyburo.)
Post: #4
RE: HP35s output displays (apologies, another question)
(10-08-2014 07:21 PM)Dieter Wrote:  do I really ask for too much if I expect students at university (!) to know that \(arcsin \frac{1}{2}\) is 30 degress or \(\pi/6\) and 0,5236 is the numeric value of this, and 1,5708 is recognized as \(\pi/2\) or 1,0472 as \(\pi/3\) ?-)

Lol, I think unfortunately that's probably a yes these days!

I was specifically instruted by my college math teacher to not waste time learning common trig functions and outputs, simply because the defacto UK calculators (casio textbook style) permitted in the exam do it for you, and that I should spend my time practicing integration/differentiation etc instead.

Until now I'd never even seen a response of Pi/6 in decimal form, and although it definitely seems reasonable, without knowing it I'd never have guessed it Tongue

Just like the internet, as tech improves, the push to learn certain facts/figures is instead directed at learning how to use a tool that figures it out for you! In some ways I definitely agree that it seems a sad state of affairs, but then again I suppose it depends on what else is added into the curriculums instead.
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10-09-2014, 03:04 PM
Post: #5
RE: HP35s output displays (apologies, another question)
Bah, now I've used RPN for a few months I just don't want to go back to the dreaded mushy casio!!

Dieter I'm going to take your advice, write these common values up and pin them onto my wall.
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10-09-2014, 07:25 PM
Post: #6
RE: HP35s output displays (apologies, another question)
(10-09-2014 03:04 PM)Kyburo Wrote:  Dieter I'm going to take your advice, write these common values up and pin them onto my wall.

Simply use degrees instead of radians – values like 30°, 45°, 60° and 90° are obvious even for the most inexperienced user. ;-)

Dieter
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10-09-2014, 08:45 PM
Post: #7
RE: HP35s output displays (apologies, another question)
(10-09-2014 07:25 PM)Dieter Wrote:  
(10-09-2014 03:04 PM)Kyburo Wrote:  Dieter I'm going to take your advice, write these common values up and pin them onto my wall.
Simply use degrees instead of radians – values like 30°, 45°, 60° and 90° are obvious even for the most inexperienced user. ;-)

Hahaha, I've just again been instructed to not use degrees any more, always radians! I'll figure it out Smile
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