Radians Question



#57

Have a question. If I take the Lat and Long of let's say LAX Airport(33deg 57min N, 118deg 24min w) enter into 35s and convert to RAD I get following.

33.57
->RAD
Answer = .585907

But if use longer manual formula of

(LatDeg + LanMin/60)*PI/180 
I get:
(33+57/60)*pi/180 = .592539

Why are these not the same? I know the manual calculation is correct, so I am figuring that I am doing something wrong with the calculator. This seem only like small issue, but this translate into bigger issue when run through calculations that I need to do.


#58

33.57 = 33 degrees and 34.2 minutes
33.57 *pi/180 = .585907


#59

Okay, maybe I am entering information wrong. How should I enter 33deg 57 minutes N? I thought it would be 33.57


#60

Never mind, I figure out...

33.57
HMS ->
->RAD
Answer = .592539

Stupid Hungarian me.


#61

Quote:
Stupid Hungarian me.

No, stupid calculator for having the key labelled "H.MS ->" instead of "-> H" like all other HP calculators.

Stefan

#62

Vincze, since you insist on using that label, I'll mention that there used to be a baseball player, a pitcher, Al Hrabosky, who called himself "The Mad Hungarian", in an effort to strike fear into opposing hitters. When he was younger and pretty good, he didn't need nor have the nickname. When he was older and less able, the "scary" name didn't help. But many fans remember him as The Mad Hungarian.


#63

I guess I not follow you. I just trying to do calculations for aviation formulary. Am I doing something wrong?

Edited: 15 Aug 2007, 12:51 p.m.


#64

Here a funny thing. I do find sin of say 100 on hp35s and I get .984808, but in MS excel, it come out as -.50637. Is something different in Excel?


#65

the Excel worksheet function expects the argument to be in radians.

change your 35s to radians mode and check!

Les


#66

What if I already convert to radians though? Meaning:

33.57
HMS ->
->rad
sin
ANSWER = .010342

but Excel show .558469

If I take .010342 and ->rad I get .000180, which still wrong.


#67

[quote]
What if I already convert to radians though? Meaning:

33.57
HMS ->
->rad
sin
ANSWER = .010342

You are taking the sine of an angle in radians but your calculator is still in Degree mode.

If you want the right answer with the keystrokes you have, put your calculator in Radians mode first--MODE 2 on the 35s. You get the right answer like magic.

Les

Edited: 15 Aug 2007, 2:11 p.m.


#68

I try it that way, but final outcome is not correct still. Let me illustrate what I have in Excel.

VARS:
LAT1 // Latitude 1
LON1 // Longitude 1
LAT2 // Latitude 2
LON2 // Longitude 2

=ACOS(SIN(Lat1)*sin(Lat2)+COS(Lat1)*Cos(Lat2)*Cos(Lon2 - Lon1))

All Latx and Lonx use (Deg+Min/60)*pi/18 so if: [pre]
Lat1 = 33 deg 57 min = 0.592539281
Lon1 = 118 deg 24 min = 2.066469834
Lat2 = 40 deg 38 min = 0.709185453
Lon2 = 73 deg 47 min = 1.2877621
/[pre]

Based on this, Excel calculate 0.623584645 Radians

I guess where I confused is I believe I need to convert all Lat and Lon from HMS to decimal (HMS->), yes? And then I thought to Radians with ->RAD. When I try in RAD mode, and just convert from HMS and not also to RAD, I still get wrong answer. I hope it just me not knowing how to use 35s, and me not be dummy about this.


#69

I to dumb to use

#70

Listen, I don't know exactly what you are trying to do, but this seems to be an angular mode issue. One thing you need to know is that Excel trig functions accept radians as arguments, and the arc trig functions return radians. No exception. If you want to get the same results on your 35S, you have to make sure the MODE is set to RAD and that all of your angles are converted first to radians in both Excel and the calculator.

Am I missing something here? I think you believe there is a serious bug in the 35s trigonometrics. Apart from the cosine bug near 90 degrees, I don't think there are. I think you are simply getting bogged down in going back and forth between radians and degrees. This is, respectfully, a high school math issue, not a calculator or Excel issue. Sort that out and all of your results should fall into place.


#71

No, I know problem not with calculator, but with me. I too stupid to use it. I sorry to have bothered you all and thank you Les and others for wasting your times trying to help me.

Edited: 15 Aug 2007, 3:29 p.m.

#72

Quote:
When I try in RAD mode, and just convert from HMS and not also to RAD, I still get wrong answer.

I have bolded your error.

Of course you have to convert your angles to radians if you are in radians mode.

I don't think the 35s is different from any other HP in this regard.

Les

#73

Here is my final hint, and then I am going to let you wrestle with this yourself:

1. Put the calculator in radians mode
2. Enter LAT1
3. Convert it to decimal mode via HMS->
4. Convert those degrees via ->RAD
5. Store it in a variable or write down the result (which is LAT1) in radians.
6. Repeat 2 thru 5 for each of LAT2, LON1, LON2
7. Compute your desired angle with your formula. It is in radians, and should agree with Excel
8. If you want to see the result in degrees, execute ->DEG

Alternately, you can keep the calculator in degree mode and skip steps 4 and 8 and you will get the result in degrees.

For Excel to agree, compute everything in radians but change the result cell to =ACOS(SIN(Lat1)*sin(Lat2)+COS(Lat1)*Cos(Lat2)*Cos(Lon2 - Lon1))*180/PI

Les

Edited: 15 Aug 2007, 4:09 p.m.

#74

There's a difference between converting to radians, and being in radian mode.

When the calculator is in radian mode, it expects all arguments to trig functions to be in radians, and it returns the answers to all arctrig functions in radians.

It does not automatically convert numbers you enter from degrees to radians, because it has no way of knowing that the numbers you are entering are in degrees.

So if you are in radian mode, you must convert all your degrees to radians before using the trig functions on them.

The ->H.MS and H.MS-> keys have nothing to do with degrees vs. radians. They always convert between hours/minutes/seconds and decimal hours (or degrees/minutes/seconds and decimal degrees).

Since aviation formulas are generally intended to be used in degrees, just leave your calculator in degrees mode and do everything in degrees. Forget about radians.

In Excel, you still need to convert to radians, and then convert the answer back. Excel is permanently stuck in radian mode.

Stefan


#75

Quote:
There's a difference between converting to radians, and being in radian mode.

That's actually an interesting problem. Why is this acting diffently from the BIN/DEC/HEX mode? With these modes, it's changing the display of a number to a different base.

Same thing, it's still the same complex number whether we are in x+iy or r,theta display.

What if when we change mode, it does the DEG/RAD conversion? Would that be an improvement?

Any thoughts?


#76

Because BIN/DEC/HEX mode and real vs. complex affect all numbers. Degrees vs. radians affects only angles. Consider calculating the value of 2+sin(45). You'd enter:

2
ENTER^
45
sin

The calculator should obviously not convert the 2, since it's not an angle.

As for the 45, you might want the calculator to convert it from degrees to radians if you're in radian mode, but how is it supposed to know that you've entered it in degrees? Perhaps you meant 45 radians!

Stefan

#77

Someone send me e-mail telling me to stop posting such "ignorant" questions as I am dumbing down the group. I apologize for this, and that was not my intention. Because of this, I wish to apologize to group and let all know that I will not post any further questions unless they are considered "worthy", or unless I have "worthy" comment.

I am very sorry, but I wish to thank all of you who help me yesterday and in previous days. I sometime get stuck with manual (I wish they had Hungarian version) as I am very old school with things, and I know that makes me a bit slower than many of you.

Take care.


#78

I'd like to apologize to YOU for the ignorant person who sent you that email.

That is/was inexcusable.

We are all at varying levels of knowledge about a great many things.

Asking questions, particularly where a language difference exists, should always be welcome.

Certainly if a previous question or two have had a readily available answer in available manuals, it is always a good idea to read through the relevant manuals and other materials before asking a second or third question. That might have saved a couple of the questions you have asked, but is it that big a deal? To me, no.

But I too am guilty of asking questions here first and then thinking to go read the manual, so accuse me as well.

Again, I'm sorry that someone emailed you with such comments. Keep your chin up!

#79

Do not worry about it, I was always told there isn't a stupid question, keep on asking, this is how we learn. What I think it deserves to be made public is the name of the "genius" coward who send you an e-mail instead of doing it on the board.

Regards, Thor


#80

I no say who it is, as I not stoop to that level. I also know what happen to snitch in Hungary, and I not want to be considered snitch.

Please know that it was not someone who posts answers to my question. It actually person who I never see before.

I know I not stupid, because I very successful business person. I have acquired many things in United States. I know I post sometime stupid questions, but I not used to programming calculator, so I not understand results sometime.

Anyhow, I go now so I not waste peoples time.


#81

Hey Vincze, don't leave!

And, don't apologize!!

There have been one or two posters here over the years that have some rather... well, STRONG opinions and are not very polite about telling others.

Believe me, over 99% of us don't mind your posts. In fact, some of them do make some of us think more. So, don't stop. Remember, your questions are from a thinking man about a bunch of basically well-thought out machines and how bad can that be, unless the critical person is so full of himself that he thinks he's smarter than most other posters here.

In fact, including yourself, this is one of the most intelligent groups of people who informally chat on the Internet on a prolonged basis! Forget about the stupid jerk who e-mailed you.

<Edit: consider this- I've just had to edit this post for grammar! Duh!>

Edited: 16 Aug 2007, 11:59 a.m.


#82

My friend Ed, I no leave. no worries.

#83

To add to the chorus: the guy who told you to stop questioning is the ignorant one.

Here's a little secret: this place is full of folks with lots of knowledge that most of their friends and family aren't interested in. So when someone asks questions, we love to answer them!

8)

So for heaven's sake, don't worry about being "worthy." You are actually a valuable contributor to this community.


Regards,
Howard


#84

Quote:
... Here's a little secret: this place is full of folks with lots of knowledge that most of their friends and family aren't interested in. So when someone asks questions, we love to answer them!

8)...


Ouch! I've been outed! Owww! I want my blanket back, Snoopy!!

#85

(An hypothetical story):

Wife: "Uh, honey, why did I get notification that we have a P.O. Box now? Are you having an affair?"

Husband: "Uh, no of course not."

"Well then why the P.O. Box?!"

(Squirming and general discomfort and a pathetic attempt at some story about the need for fixed adresses etc)

"You are doing WHAT? Collecting CALCULATORS! The children need SHOES and you're on ebay buying old calculators? How boring!"

Edited: 16 Aug 2007, 12:42 p.m.

#86

Not necessary to apologize!

We need all types of people to post questions here. That way we all learn. Since my arrival here about 8 years ago, I have learned about cultures, some linguistic variations in spanish, and now some Hungarian.

Please don't let some little person make you think less of yourself or your questions. I try to read every one's questions, and a lot of answers (including Ebay). I do sometimes find some of the answers to be not nice, but overall, this is still a better place than 90% of the places on the Internet. And, if you stop posting, the jerks win.

My advice: please continue to post and make this forum the useful place that it is.

#87

Gene got to you first but I was going to say something similar. Welcome to the world of HP calculators and especially to this forum.


#88

Well can I ask a stupid question? I read but I am not sure that whether Sin(X) on the 35s and Sin(X) in Excell give the same result or not?


#89

Chan, my friend, I give short answer. Yes and No. :)

If I put calculator in RAD mode, then I get same result in Excel. It appear Excel convert on the fly to Radians. I never knew this. It makes me wonder what high level programing languages do as well, as I have never really tested either, but I would think it would be same as Excel.


#90

Quote:
If I put calculator in RAD mode, then I get same result in Excel. It appear Excel convert on the fly to Radians. I never knew this. It makes me wonder what high level programing languages do as well, as I have never really tested either, but I would think it would be same as Excel.

In mathematics, the trigonometric functions are always defined in terms of radians. This is because radians are the most "natural" unit for those functions. For example, in radians, d(sin(x))/dx = cos(x), while in degrees, d(sin(x))/dx = cos(x) * pi / 180.


High-level programming languages all follow this convention; this is true in BASIC, Pascal, C, C++, Java, and Excel, just to name the ones I'm personally familiar with.

This means that Excel doesn't convert its arguments to radians on the fly; it treats the arguments to its trigonometric functions assuming they are in radians. The only times when arguments get converted "on the fly" is when you are using trigonometric functions on calculators, while they are in DEG or GRAD modes.

I think what got you confused was when you were trying to use the Great Circle Distance formula, where you actually have *two* conversions to worry about, namely the conversion between degrees-minutes-seconds (which is used in navigation) and decimal degrees, and then the conversion between decimal degrees and radians. As long as the calculator is in DEG mode, all you need to do is the H.MS -> H conversion before applying sin or cos; if the calculator is in RAD mode, you need to do H.MS -> H, and then DEG -> RAD, before applying sin or cos.

- Thomas


#91

Quote:
I think what got you confused was when you were trying to use the Great Circle Distance formula, where you actually have *two* conversions to worry about, namely the conversion between degrees-minutes-seconds (which is used in navigation) and decimal degrees, and then the conversion between decimal degrees and radians. As long as the calculator is in DEG mode, all you need to do is the H.MS -> H conversion before applying sin or cos; if the calculator is in RAD mode, you need to do H.MS -> H, and then DEG -> RAD, before applying sin or cos.


Why, though, if you are in RAD mode, do you have to convert from DEG -> RAD? Is it because I am placing information that is in degrees? Meaning 35 degrees 24' 00"

#92

Quote:
Why, though, if you are in RAD mode, do you have to convert from DEG -> RAD? Is it because I am placing information that is in degrees? Meaning 35 degrees 24' 00"

The calculator does not know if the number you enter is in degrees or radians. It is just a number. When the calculator is in DEG mode, the trigonometric functions assume that the value in the X register is in degrees (decimal degrees, not degrees-minutes-seconds). When the calculator is in RAD mode, they assume that the value is in radians.

- Thomas

#93

Sometimes we take many things for granted and sometimes we need simple questions to help us rethink those things and discover something new. Worthy members of this community have given you (and me, by the way!) the best answer to your apology.

Keep those questions coming...I am learning too.

Regards,

Miguel

Edited: 16 Aug 2007, 8:35 p.m.


#94

Aren't we all still learning. Particularly when in involves the 35s with its improvements, shortcomings, and its deviations from past RPN models.

tm


#95

While we're still on the subject of apologies, I'd say the 35s is something HP shouldn't have to apologize for, either. I'd say they got it right for the most part (see threads about the checksum issue). It's very hard to be completely perfect.

#96

I have to admit I was getting a little grouchy because your dilemma seemed so clear to me and I was at a loss at to try to explain it more clearly. Regrettably, I would not make a good high school math teacher.

That said, I think you have the right and privilege to post whatever you like of even passing relevance to the aims of the Forum. If someone doesn't want to read your stuff, they don't have to.

I have to scold you for this "stupid Hungarian" insult you heap on yourself whenever you bump up against something you don't know. I can't imagine it is a very pleasant experience to so harshly and inaccurately criticize yourself for something so human as not knowing everything. If I called myself a "moronic Canadian" everytime I bumped into something that stumped me, I would be so depressed from the self-abuse I wouldn't be able to get out of bed in the morning.

Take care of yourself, and enjoy the 35s.

Les


#97

I not mind calling myself "stupid Hungarian". It my way of laughing at myself. It really no different than when I work on something and I struggle with it for hours and then finaly figure it out and say, "Vincze, you dumb a*s".

Now if someone call me stupid Hungarian, yes that would hurt and diminish my self worth. I know I am only human, and I know that I not know everything, so until I know everything (which never will happen) I am a stupid Hungarian.


#98

Hello Vincze,

Lanczos, Eotvos, Von Neumann, Eugene Wigner and Edward Teller, notable physicists and mathematicians, as well as my longtime friend Philip, who taught me a thing or two about computers and life, come to my mind when I think about Hungarians. Yours is a land of remarkable, if not gifted people, so there is no such thing as a stupid Hungarian who should not post here.

You are anything but stupid, Vincze, and you should keep posting. For occasional posters like me in particular and all the other contributors in general it is good to read from people like you.

However, in the 1950s there was a "theory," so to speak, circulating amongst the non-Hungarian colleagues of some of the people I mentioned above: Hungarians are from Mars. The reasons:
1. They are very smart.
2. The Hungarian language is different from all the other languages in Central Europe (and presumably on Earth.)
3. They are like gypsies (the reason why they came from Mars in the first place.)
You can find the whole story in "The curve of Binding Energy", by Roger (or it was Richard?) McPhee. The point is, beyond saying "stupid Hungarian" as a way to express one's inability to grasp the obvious, ther is no such thing.

Please keep posting and disregard the occasional idiot who e-mails you adivising otherwise.

My two cents.


#99

Quote:
2. The Hungarian language is different from all the other languages in Central Europe (and presumably on Earth.)

Isn't it akin to Finnish?


Quote:
Quote:
2. The Hungarian language is different from all the other languages in Central Europe (and presumably on Earth.)

Isn't it akin to Finnish?


Wise people claim there is some relationship between these two languages, and Japanese next. AFAIK Finnish, that must a pretty loose connection. But Vincze knows better for sure.

If you are looking for a *very* special language in Europe, turn to the Basque people living in northern Spain and southwestern France. Their language is supposed to be a remainder of the oldest languages of this continent (for US-American readers: I'm talking about some *thousands* of years :).

Edited: 19 Aug 2007, 1:40 a.m.

I had the pleasure of working for Zoltan Herger in 1989.
(DAGS if you don't know who he is).

Based on my experience with him, my stereotype of Hungarians is:

Hardworking, Industrious, Pleasant, Watchful, Humorous, Freedom Fighter...

(Now if there are ANY Hungarians in this group that don't fit my stereotype, PLEASE leave me pleasantly ignorant!)

Ren

dona nobis pacem


Quote:
Hardworking, Industrious, Pleasant, Watchful, Humorous, Freedom Fighter...
I think most ethnic people are like this. One thing about Hungarians, is they really like jokes. They also take very seriously math and science. You may or may not know that we invent BASIC language, the ballpoint pen, atom bomb, and other things. Granted, these were not all invented in Hungary, but by Hungarians.

Also, most Hungarians are very giving. We give you shirt off our back if you need. Sometime people say this our downfall and we get taken advantage because of. With me, I don't see it that way. I rather give, and try and help person. Sure, someone may take advantage of me sometime, but most time, I helping someone and not take advantage of me.

We also very proud of our food. It very bad manner if you offered food from Hungarian and you not take. Many time it best not to ask what is in food. ;)

Hi, Vincze;

(additional stuff) the most important words I forgot (writing in a rush has such effect... Sorry!). I would have answered to your posts promptly, as many others did and would have done, if the chance was given, without any additional comments or off-line e-mails. I actually did not read them in time to add something that other contributors had not yet add, so I just read them. Also, I do not own an HP35S (yet, at least), so I would never be sure if my answers were accurate. As others have already mentioned, we love helping people to use their HP calculators, and you are no exception at all. And thanks for your kind words, Hrast... (end of additional stuff)

I am not posting too very often here because of private, personal reasons. I realy like this Forum´s environment and neighborhood, people are friendly and handy... BUT not all of the ones that actually visit this forum (mostly read, seldom post) follow some simple, common decorum rules.

I wrote about this a few times before: I'm a guest here, both as a foreigner (I'm from Brazil, as I mentioned beside my name) and as a contributor (in fact, Dave Hicks is the only one that can tell 'I´m not a visitor' in this particular way...), so I believe I must behave accordingly. Even if it is only to deserve staying amongst all of these good people, sharing so too many good and important information. (In fact, I cannot think of behaving differently in real life, wherever I am, whoever I'm dealing with)

I'm also a teacher (some guys are also tired of reading about this, too...), and I cannot consider a dumb person the one that tries to learn. In fact, I tell my students: 'There is no such thing as a dumb question; there are, indeed, dumb people that cannot give a question the deserved answer and respectfull attention'. Well, sometimes I shorten this to lesser words, though...

Anyway, as you can see (and read) from the others who followed your post up (some of the current finest representatives of this forum's contributor staff), people here care for each other. Could it be better? I guess not. I myself feel I'm home here, no pun intended at all.

Now it is my time to go ahead and deal with my daily stuff. I just could not leave without posting this time.

Best regards.

Luiz (Brazil)


Edited: 17 Aug 2007, 3:02 p.m. after one or more responses were posted


Hi Luiz ... Glad to see you here again :-)

Hi, Luiz-Claudio, nice to hear from you again here.

Vincze, my friend, summarizing up all the previous posts, you are simply not allowed to leave ... we will not let you go away.


Thank you my friend Nenad. It is nice to see you again.

I take beating from calling myself stupid Hungarian, so I will no longer say that. I will call myself stupid American. ;) No, I just kidding, I think I smarter than stupid American... but maybe not smarter than smart American. I think I just dig hole for myself.


Quick! Use your 35s and calculate the depth of the hole and the amount of thrust needed to get you out! :D


I think my hole taking on water. ;)

Hello Vincze,

From some of your previous post, it's clear that most of your problems stem from the fact that your handbooks are written in English, rather than Hungary. You're right, manuals written in a language not our own sometimes look Greek to us (I wonder how the Greek would say that :-)

I hope the following expresses this feeling correctly :-)


Once there was a freak
Who was always up the creek.
Surely knowledge-hungry
Was this guy from Hungary.
But, alas, his books were 'n Greek!

Don't worry about the word freak. Once someone said we're all freaks here. My knowledge of English is not better than yours, but I think this shoudn't be considered offensive, quite the other way around. I am just a guest here, like everyone else, but I ask you please to stay :-)

Best regards,

Gerson.


Edited: 19 Aug 2007, 8:35 p.m.


You know, I remember onetime being with Hungarian friend in America, and I overheard a couple who were Asian, talking their language, and I ask my friend, "I wonder if we sound as goofy to them as they sound to us?" It funny what we think is normal sounding and what not. Yes you are right, reading English is a bit challenging at times. I can talk it well, but writing and reading have always been hard for me. My wife keep asking me why I try and get MBA since I have done well in life, but I want American degree, not just MBA. I'm sure I could get MBA in Hungary very easily, but getting degree in USA very hard sometimes.

Anyhow, thank you for kind words my friend.


Hi Vincze.

Of course I fully agree with what others already said about the importance you ignore the *real stupid*

people that sent you that e-mail, AND you go on posting whatever question you may have,

and for a couple of reasons, at least:

1. often, those *stupid* questions make somebody else say to himself "that's what I would have liked to ask, but don't know if I ever would have the courage...
So thanks to that Hungarian guy!"

2. you have not joined the forum since a long time, but did you notice how was lively and bright the debate after your inputs?

Now, Vincze, my friend (I hope you don't bother if I borrow your nice expression ;-) and my neighbour (well, almost...) please keep on

contributing with your "thirst for knowledge" ;-)

Warmest regards.

Giancarlo


Giancarlo, my friend. I not mind at all you using my saying. We are all friends here, and I always think it nice to say to people.

I will continue posting. I not notice one thing you said though, that everything lively after I post. I wonder why that is. I am just a humble man who want to be student of life. I know many things, but many I do not know. I assume when I die, and am blessed to meet my Maker, than maybe I will be gifted by Him, and know everything. Until then though, I am happy with only knowing a little.


Possibly Related Threads...
Thread Author Replies Views Last Post
  CORDIC in Degrees vs. Radians Mike Fikes 5 739 07-24-2011, 04:49 AM
Last Post: Eric Smith
  Angles in radians using expressions with PI?? Alex 3 614 03-18-2007, 02:09 AM
Last Post: Alex
  Sin(Pi) in Radians Mike 33 2,999 08-29-2004, 02:58 PM
Last Post: Eddie Shore
  HP 41C - Converting From Radians to Degrees Mark McLean 14 1,365 04-28-2004, 10:45 PM
Last Post: David Smith

Forum Jump: