The Sphinx's Lair

5:52 AM

@Alconja I think that a meta post might not be a bad idea. Not because your answer is not OK. Exactly the opposite - it is perfectly OK. And it might be a nice idea to have a CW answer (so that there aren't multiple answers) for Feedback on a puzzle. It also might be nice to have it as a feature - i.e. a Feedback section at the bottom, but probably this is too much to ask.

Not that you should do it CW in your case - if nobody else wants to give feedback, you should leave it as it is.

duzzy

6:13 AM

@manshu lol that's awesome.

I think this place can be valuable for me. I really like going to information security conferences, and there are always hacker challenges at those things. I'd like to participate in creating some of them, and this seems like a great place to learn how to craft good challenges.

11:00 AM

@MariaDeleva I have the weird feeling that your puzzle pertains to one of the lesser-known logic puzzles rather than the usual ones...

Well, it is hard to say for me whether it is lesser known or an usual one. I have been asked this very same question at an interview and searching it online claimed it is often used in interviews. But how often is often, who knows? :)

Even if you don't know the puzzle, knowing that it is not equations, you can still logically deduce it.

I think I got it...

Post your answer :)

Never mind...

Got too excited..

You sure, your colleague wrote the answer correctly??

The answer is correct.

Now I found a site which states that this is the most common interview puzzle. Not that everything is true on the Internet :)

11:18 AM

Posted an answer

Although I am not terribly sure..

It just feels that is it

There would have been more rows in this case, and more letters.

Exactly the reason I was not sure... I had the gut feeling that it would be one of the river crossing problems.. and this was the shortest..

Gareth was right that AB means A and B.

12:08 PM

@Deusovi do you yet have a specific idea of what you want to do after graduating? (it's perfectly fine for the answer to be no at this point)

Deusovi

12:26 PM

@GarethMcCaughan Honestly, not really? I've thought about becoming a professor, but I've heard a lot of bad things sbout academia.

user189275

@Deusovi: From which college you're graduating ?

12:45 PM

Sep 19 at 19:43, by Mithrandir

@PuzzlingMeta That won't get many puzzles...

@Mithrandir 18 puzzles. :) Fun challenge.

@Deusovi Getting a decent academic job is really difficult; you need to be somewhere on the scale from "astonishingly good" to "astonishingly lucky", I think. And the pay isn't great, and in the early parts of your career it's downright terrible as is your job security. But ...

... on the upside, you get to spend your working day thinking about interesting things (in principle; in practice you may find a lot of it is teaching and bureaucracy) and if you make it a reasonable way up the tree the pay isn't so awful and your job may impress some people :-).

If you have what it takes to be a professor of mathematics or computer science you probably also have what it takes to be quite successful in programming, data science, industrial R&D, quantitative finance, etc.

user189275

Anybody knows where someone can see the surroundings of the Kryptos Sculpture in 3D ?

Langley? :-)

user189275

@GarethMcCaughan: What is that ?

1:01 PM

Where the CIA headquarters is. Isn't that where the Kryptos sculpture is located?

(yes, it is)

user189275

@GarethMcCaughan: Yes, but you can understand what type of answer I

user189275

am wanting.

@ArbitraryKangaroo I see you changed your name. :)

user189275

1:18 PM

@MariaDeleva: You remembered ?

user189275

How did you notice ? By looking the profile picture ?

user189275

Update: I asked a very stupid question.

you did? Where? :)

user189275

@Sconibulus: Everywhere. I keep asking them. I just meant the questions before the declaration.

@ArbitraryKangaroo the gravatar seemed familiar, so I decided to take a look at the profile :)

user189275

1:33 PM

@MariaDeleva: How it (the gravatar) is genarated ? Randomly - or anything related to the names ?

Q: PSA: please don't ruin puzzles by de-spoilering a spoiler-tag answer

@ArbitraryKangaroo I think it is somehow related to the email you registered but not really sure - especially considering the fact it can change "randomly" at some point. Not really random, but have no idea what the reason is.

Stewie Griffin

@LukasRotter ftr: I'll accept your answer soon, I just like to keep the challenge open a while before I do so. Let others try before it has that big green mark... :)

Puzzling Meta

1:48 PM

0

This is about exactly the thing it says on top: please do not say openly and directly in comments, the things in an answer which were spoiler-tagged. There are good reasons for this: 1. It makes the puzzle harder to solve for other people. When you say "X is a good attempt" or "Y is really clos...

discussion spoilers

Hmph, no PSE mods around.

@Emrakul Would I be right in saying that according to PSE policy, copied puzzles will be deleted if they don't provide attribution, but if they do provide attribution, you won't bother checking the details of the source site's copyright rules and will only remove the question if they file a DMCA takedown notice or something? (see comments on this question)

I.e. you do police the site for plagiarism but not specifically for copyright violation?

@Arka yes, I do understand what kind of answer you were after but, not having a useful answer, I thought I would offer a useless but hopefully slightly amusing one instead :-).

user189275

@GarethMcCaughan: Yeah, it was amusing and useless. I have heard some people did an entire 3d mapping of the area and made it accessible online, but after (searching for around 15~30 second max) some searching I didn't find any.

@ArbitraryKangaroo yes, I was MD for some time, but it turned out to be a mistake

user189275

@MariaDeleva: Oh ! I remember more. "What's in a name ? If you call MD by Maria Deleva, the puzzles would be same. .... " The whisper continued. Then it went to discuss somewhat a "REJBAS" or something like that, I couldn't understand.

user189275

2:02 PM

Any more princess + Laniff III puzzles ?

@ArbitraryKangaroo you want them to continue their story? :) I should think of something...

user189275

@MariaDeleva: May be, or may be their heirs. Anything, but just any non-wordplay/cc puzzle, I am tired of those wordplays/cc (I ain't saying they're not good, but occasionally some different taste is wonderful) of you.

user189275

And please make it a bit long-lasting.

OK. I will put some work to it. But can't really say when it would be ready as I haven't yet shaped an idea.

It could take a while.

user189275

@Randal'Thor: Can users suggest new features/badges in an SE site ?

2:09 PM

@ArbitraryKangaroo I think that'd be Stack Exchange Meta

user189275

@Sconibulus: I would like to see 1. Floating bounty (i.e 1000+ bounty with no particular deadlines) 2. PSE specific badges like "Riddler" "Cryptographer" "Unsolved mystery solver" etc.

but unless you have an idea that you can already track through the data explorer, encorages helpful behavior on an average site, or StackOverflow specifically; you probably won't get anywhere

PSE specific badges are probably a non-starter

open ended bounties have more of a chance, but I don't think they're particularly likely

@ArbitraryKangaroo there are already badges for the tags.So you can get a badge in "riddle", "cipher", etc.

I think the reason for time limits is so that the bounty is automatically awarded to a good answer, even in absence of a great answer

basically to keep the bounty poster's expectations from being too high

user189275

Also I don't see any sane point why the bounty amount vanishes into thin air after it expires.

2:15 PM

@ArbitraryKangaroo If they're PSE specific, post a feature-request on PSE meta. If they're general to all of SE, post one on main meta.

@ArbitraryKangaroo the idea is that you used the bounty to promote the question. Mission accomplished. It is basically like paying for an ad somewhere - even if it doesn't have the desired effect, nobody will reimburse you.

@ArbitraryKangaroo I very much doubt you'll be able to persuade the powers that be to change the workings of the bounty system, or to create site-specific badges (other than the tag badges Maria mentioned, which pretty much cover your suggestions already).

@ArbitraryKangaroo puzzling.stackexchange.com/help/badges?tab=tags

user189275

@Randal'Thor These badges exist? I am very unsure.

@ArbitraryKangaroo Scroll down to "Tag Badges" on that page.

Here are people with a bronze riddle badge: puzzling.stackexchange.com/help/badges/94/riddle

2:22 PM

@MariaDeleva Wow, so many people have that one these days. I remember when there were just two of us.

:) You are the only one with a silver badge :) That can comfort you.

user189275

(i.e. Why mathematics and riddle only have silver counterparts too)

@MariaDeleva And well on the way to gold! Unfortunately there are hardly ever any duplicate riddles, so the dupehammer powers for a riddle gold tag badge won't be worth much.

@ArbitraryKangaroo Bronze, silver, and gold tag badges can exist for all tags with at least 100 questions. On Puzzling, nobody has been awarded a gold one yet, nor has anyone yet been awarded a silver one for anything except mathematics and riddle.

user189275

Oh yeah. I hadn't understood actually.

user189275

@A.Mirabeau: 12 hours has passed since 23rd September ? I keep losing track of time.

2:27 PM

My rant about riddles on my profile description apparently backfired; riddle is my second top tag... But these points are mainly because riddle was a "sub-tag" from puzzles... People will think I'm a hypocrite :P

@ArbitraryKangaroo Are you the user formerly known as Arka Karmakar? That avatar looks familiar ...

user189275

@Randal'Thor: I forgot.

user189275

oyiekhpaukrvrzqhdittaxgvdzdfyrjamonvnfxsonjucbersfx

user189275

qkcimcmqxbfzhampsp.

user189275

(Last one is separate)

2:36 PM

@Rand my visual memory is rubbish but I just assumed ArKa = Arka Ka... (and the writing style seems similar enough to make it plausible).

though maybe we shouldn't be saying this out loud, if the aim is a change of identity

user189275

@GarethMcCaughan: I'm actually curious about the "writing style" that makes it obvious.

oh, sorry, I don't mean that your writing style makes it obvious; only that it doesn't refute the hypothesis

(incidentally, I didn't see whatever you removed)

user189275

@GarethMcCaughan This is internet, and here people discuss and criticize ideas, so you're (obviously) free to say whatever you wish regarding that, without any remorse.

user189275

I am actually curious, what is the the writing style ?

@ArbitraryKangaroo In case anyone wonders: Vigenere cipher with key ArkaKarmakar: ohyeahyouarerightichangeditforsomenenonsensicreason.

user189275

2:42 PM

@GarethMcCaughan: Like this (From wisdomofchopra.com ; A hilarious site): "It has been said by some that the thoughts and tweets of Deepak Chopra are indistinguishable from a set of profound sounding words put together in a random order, particularly the tweets tagged with "#cosmisconciousness". This site aims to test that claim! Each "quote" is generated from a list of words that can be found in Deepak Chopra's Twitter stream randomly stuck together in a sentence."

user189275

?

I'm not sure how to answer that, sorry. Again, the point isn't that there's anything particularly peculiar about it -- just that when I read the comments of ArbitraryKangaroo I don't think "oh, no, wait, there's no way Arka Karmarkar would ever have written that". I don't have any particularly explicit characterization of anyone's writing style in my head.

don't worry, you sound entirely unlike Deepak Chopra.

user189275

@GarethMcCaughan: That was a joke, visit that site, and have a hearty laugh.

yeah, it's OK, I didn't think you thought I was accusing you of being Chopraesque.

user189275

@GarethMcCaughan: It is completely pointless to care about what others care about your comment about them, alteast here.

2:46 PM

I prefer to avoid giving offence if I can.

I did find this puzzle elsewhere on the internet, but it seems to be found in a lot of places, so it should count as a 'chestnut'.

user189275

@LukasRotter: You did it by frequency analysis ? So try this (no personal key):

(still going through my old puzzles to see if I need to edit them for attribution)

user189275

aowodfazkmhlqmvgrdkgsxuzdkbkkjgixblcvbiaolzrpiycjifmoxamcbctgudsbciawkdlqihdxbvo‌pgodkzqnlofniycwceapvntbmwsyglcjvvritfkctyimsjou

@ArbitraryKangaroo Well, yes, by Kasiski's Examination. Although it wouldn't have been necessary because the key is the obvious key one would use in this case :P

user189275

2:49 PM

@LukasRotter: Try the next one.

user189275

"aowodfazkmhlqmvgrdkgsxuzdkbkkjgixblcvbiaolzrpiycjifmoxamcbctgudsbciawkdlqihdxbv‌o‌pgodkzqnlofniycwceapvntbmwsyglcjvvritfkctyimsjou"

"qxyzkriptossculptorsandbornsasitentsedthatpartforyoozemuskeenglikethi
stustopfreq‌analaisysandrandomqyxyanumbarsorlettarsscattered"

user189275

@Sconibulus: How ? So quick ?

there are a couple of websites out there that do vigenere-cracking

and I've written my own code for it (though empirically it underperforms the websites)

I threw it at this site: mygeocachingprofile.com/codebreaker.vigenerecipher.aspx which guessed "vryptkf" which I then guessed Kryptos from

apparently there's some sort of frequency analysis it does by magic

user189275

2:53 PM

Yeah, it's trivial, because I ain't Sandborn (?) and 1 minute is not 15 years.

@GarethMcCaughan oh, cool, how does it work?

@Sconibulus Yeah, it analyses repeated patterns, guesses the key length by that, performs frequency analysis on each "row" (e.g. every 7th character) and maybe adds some dictionary attack/match sometimes.

Atleast that's the way I do it :/

my program? it has a little table of rough letter frequencies; it considers different key lengths; for each key length it considers each of the offsets mod (key length) and looks for the shift (for that offset) that maximizes probabilities; it then looks for (key length, shifts) pairs that maximize overall likelihood.

this is pretty stupid

How does it guess the key length?

in that e.g. you can surely do a lot better with digraph freqs etc.

I just try all key lengths

2:55 PM

from 1 to 100, or longer?

1 to text-length?

for comparing different key lengths I should really use some sort of "information criterion" but I don't because I'm lazy

I just use 1 to 12 or 16 or something

very long Vigenere keys are effectively just one-time pads

with a super-long message I'd consider longer keys

@GarethMcCaughan How long does you program usually take on a single code?

Hmm, is Offset Vigenere a thing that ever gets used?

2:57 PM

(sorry, "information criterion" means penalizing longer keys when computing the log-likelihood to make up for the fact that for a longer key you have more options to choose from)

sub-second

like, for example eykeykeykeykeykeykey...

oh, wait, never mind

@GarethMcCaughan Wow

I also make it notice when there are multiple shifts that produce near-best likelihood

that just ends up being the same as key 'eyk'

so it can say "I found 120 candidates and here they are"

since in practice for short messages the program usually gets it at least slightly wrong and you want to eyeball it

2:58 PM

@GarethMcCaughan Which language?

Python

which is slow but it really doesn't matter for this because there are no very intensive calculations to be done

again, the ones out on the web do better

Oh, okay.

probably because their authors have taken more trouble to make them better

I'm just learning python

It's cool

I originally threw mine together for a talk at my company (we have, or rather had, a tradition of occasional lunchtime talks on interesting usually-non-worky topics) about cryptography, so it needed to be short more than it needed to work well

user189275

3:01 PM

@Ankoganit: Online by yourself ?

@ArbitraryKangaroo Yup

user189275

@Ankoganit: Interactivepython is a moderate site, after using for one~two hours, you can find why its moderate.

@ArbitraryKangaroo Hmm, I'll check it out. Thanks

user189275

It teaches with tons and tons of encapsulation, which you (the learner) obviously can't understand. That's why I hated it, but there's no other good sources online which assumes zero knowledge.

I've not tried anything except the documentation yet :D

My first (non-trivial) program was a (purported) 4x4 sudoku solver which was a total failure :P

3:07 PM

Did it ignore all inputs and always output the same solved sudoku?

I had a friend who did that one once...

@Sconibulus Nah, it always ended up running into an infinite loop

@Sconibulus That's genius!

Because of some faulty indentation I guess

Haven't tried debugging it

It was actually an accident, the inputs were treated as penciled, so it didn't actually always output the same one, but it often did

BTW, how mathy puzzles are OK to post here?

I made a problem some time back, which I want to post

user189275

3:17 PM

@Ankoganit: Which problem ?

It's quite easy, but nice.

@ArbitraryKangaroo Uhh, I was thinking I'd post it on the main site, you'll know then

Is it straight maths?

@Ankoganit Is it straightforward application of mathematical techniques?

Nothing more than elementary high school maths

@RosieF No

I think so at least

user189275

@Ankoganit: When you are posting it ?

3:27 PM

@ArbitraryKangaroo Haven't decided yet....probably now or tomorrow morning

user189275

@Ankoganit: Why not now ?

I'll have to find it

That might take some time

Or maybe not if I get lucky

And I need some work on its formulation to make it look puzzly.

@Ankoganit some puzzles here are very mathematical; best is probably to take a look at puzzles tagged with the mathematics tag

The thing is, I've at least two concerns:

1. It might be too easy for you people

2. We put it on an *unofficial* contest, so if I 've to link to that contest, it would be a spoiler.

I think I can just mention that it's mine, right, and avoid any mention of that contest?

@Ankoganit Trouble is that if it gets answered here while the contest is still running, people in the contest will get an answer they don't desrve yet.

or even if we get incomplete answers here, that might give undserved clues to people in the contest.

e

3:37 PM

@RosieF The contest ended long back

In May IIRC

@Ankoganit OIC. Thought it was still running. Awkward word, put. It's present tense and past tense.

3:51 PM

@Deusovi What should I do to get suspended for 3 months, starting from January 2017?

@Sid ... why would you want to get suspended?

GentlePurpleRain

@Sid Nothing. If you're looking for a way to help yourself limit your activity on the site, there are many software solutions that can help. Here's one: chrome.google.com/webstore/detail/stayfocusd/…

Q: Pheno Menon's number challenge

Alright, I finally posted it:

1

Today Professor Pheno Menon challenged me with a puzzle: "I will give you a composite number $n$. You need to give me a list of $n$ integers, all between $1$ to $n$ (those two included), so that the sum of their cubes is equal to the square of their sum. Can you always do that? I said "That's e...

mathematics

I'll keep my fingers crossed

@GentlePurpleRain I prefer this simple one:

@Randal'Thor I can't concentrate on my studies and on march 2017 I got my board exams...

4:02 PM

@Randal'Thor the problem is I have forgotten my password. I am always logged in

user189275

@Sid: CBSE ? I have "Madhyamik" on 2017 !

@ArbitraryKangaroo yep

user189275

@Sid: X or XII ? I have to appear for X board next year. It's horribly stupid.

user61230

@Randal'Thor We don't deal with legal requests. We just do plagiarism/attribution checks.

4:05 PM

@ArbitraryKangaroo XII

@Emrakul Right, that's what I thought. Thanks for confirming!

@ArbitraryKangaroo It's still better than the old syllabus.

@Alconja ^^^ relevant to our meta comment discussion

user189275

@Ankoganit: West Bengal class X syllabus (I am mugging exactly that) ? It is better ? Completely nonsense.

user189275

I have tons of anecdotals and experimental evidence to prove my claim

4:08 PM

@ArbitraryKangaroo Quite true.

I am just saying it was even worse last year

(when I gave it)

@ArbitraryKangaroo How's the math now?

@Ankoganit Whole education system is stupid. You could give them all explanations and teachers would scream it is not in the book!

user189275

@Ankoganit: You see, I find zero point in introducing "Compound"(Chakrabridhhi) or Saral (I don't know the English) percentages, or completely unnecessary jargons in everywhere. You can't just use symmetry or such stuff in your proves, otherwise the gods would quail in terror. And the teachers, atleast in my school, doesn't know anything what they are teaching. When I asked what is the point of using Pi - based degree system (Brittiya paddhati; the english isn't coming up now) to my teacher.

user189275

(cond)

Radians?

user189275

He replied "Otherwise you wouldn't get marks solving those questions" ! (Wah ! ) Another day, I just wrote nonsense things in a proof, (I used it as an experimental evidence to prove the teacher doesn't know nothing; Using random greeks words, and the greeks spelled "NoNSenSE"), the teacher just replied "Yeah, it is good , it is in higher class (?!?!), but don't use in Madhyamik". The physics teache has simply mugged up everything.

user189275

4:13 PM

(cond)

@Sconibulus yep

user189275

And each day the algorithm is as follows: Come -> Ridicule me for not mugging up and I'm getting spoiled doing these nonsense things -> Turn back and write "notes" (Q & A to be written exactly in exam) -> Goes back. When I ask him about doing experiments, he just replied "These are in XI and XII. Not for you".

user189275

(cond)

@ArbitraryKangaroo LMAO

I wish I had the courage to do that

user189275

Our Headteacher, I wonder how he became one, is a complete nonsense. He once called my mother, (I become a class topper (the best mugger) somehow doing nonsense, that's antoher story), and ordered her to stop myself from doing nonsense things (these) online, and "focus" for Madhyamik. I used to perform (well it had gone for 12 ~ 13 days until it was stopped) experiments with home items, my mother told him, and he replied "Experiments are for scientists. Not for you".

user189275

4:17 PM

(contd; Jus few more)

I am sure, the other guys are just sitting back and enjoying this...

user189275

History teacher is also nonsense, has zero idea about the world. About all the "math" teachers I have interacted in real life, 100% chugs it, and things symbolic manipuation and performing rote task is math. I purchased a wonderful book, "Measurement" by Paul Lockhart (It costs a bit more in India); it actually pursued math as a beautiful thing; but I don't have the time to read it, because I have to score more. I am now admitted in so called "Pathfinder", by my parents,

user189275

(cond; not lnog)

user189275

and the only purpose is to score "95% +" in exams. Well, a so called "Mock exam" is going on now, from 27 Sept ~ 5th October, and I'm relaxing because the next one is mathematics, and you obviously know it's nonsense.

user189275

(Last portion writing):

4:23 PM

(sorry for interruption, but speaking of Lockhart, I think everyone should read these 25 pages of perfect truth )

(Oops will be AFK for some time)

user189275

But I have some counter anecdotes too. 1. One English Teacher, nicknamed MB, is very rational, criticized authority freely, and encourages us to do that. 2. The teacher who checked my math answer script didn't cut my marks when I used symmetry in a proof or the fact that arccos is 1:1 in [0,pi/2] in my answer script (to evaluate symbolic nonsnse like cos(*) = cos(30); 30 = ? ).

user189275

3. 3. My parents allow me to do PSE or other stuff as long as I study around 3~4 hours attentively (i.e, without euphemism; mug hard). Finished.

user189275

------------##

user189275

@Ankoganit: What is LMAO ?

user189275

* 2. The teacher not in my school, but in PF.

4:34 PM

@ArbitraryKangaroo "Laughing my a*** off".

user189275

There should be fours stars, Isn't it ?

That was quite a rant...

@ArbitraryKangaroo I'd always use "Laughing my ASCII off."

user189275

@Sid: Yeah, these things happens extremely regularly, so I hate it, doing pointless stuff. The main points of the rants are almost same. Same stuff happens there (in your board + school ) ?

@Ankoganit I have made several decent and well-working things. But when I tried making simple Tetris on C++, it was so buggy, that I called it Buggy Tetris :) or something like that. You can't beat my Buggy Tetris' bugginess :P

user189275

4:45 PM

@Neon612: What is the meaning of the words ?

user189275

wisdomofchopra.com

ASCII

ASCII (/ˈæski/ ASS-kee), abbreviated from American Standard Code for Information Interchange, is a character encoding standard (the Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII). ASCII codes represent text in computers, telecommunications equipment, and other devices. Most modern character-encoding schemes are based on ASCII, although they support many additional characters. == Overview == ASCII was developed from telegraph code. Its first commercial use was as a seven-bit teleprinter code promoted by Bell data services. Work on the ASCII standard began on October 6, 1960...

Basically a less offending way of saying what Rand said earlier

user189275

I still can't understand what's the contextual meaning of ASCII in place of A4*

Yeah, sort of, except we do experiments from a certain book. Plus am pretty sure that NCERT would decrypt to "wrong" using some puzzling algorithm. Half the stuff written there is wrong, but who cares? We have to mug up to pass the exams

Its more of a US based saying

4:48 PM

Do I have to add the computer-puzzle tag if the puzzle contains code? No deep knowledge is required, the solver just has to know that e.g. width: 42px; in CSS means that the width of object x is set to y, which is kinda self-explanatory. I think people that search for "real" computer-puzzles would not look for that kind of thing, so I'm not sure.

a*** is British, while a** is US based

user189275

@Neon612: This is not EUSE, but I still don't understand. What is Laughing my Vignere of f ? Laughing my Playfair off ?

I've never heard of those before

ASCII sounds like Ass, that's the extent of the joke

user189275

Oh ! But how you pronounce "ASCII" ? I pronounce it as Ask two, but it is wrong way probably.

4:51 PM

"ASCII (/ˈæski/ ASS-kee)" from the wikipedia article

@Ankoganit Oh dear. He has a nice conclusion he wants to convince us readers of, but in trying to convince us he writes a lot of bullshit.

user189275

@RosieF: What thing ?

@RosieF I actually failed to make it past page 2

@ArbitraryKangaroo Lockhart's Lament, which Ankoganit linked to a few minutes ago.

user189275

@Sconibulus Watch this: youtube.com/watch?v=V1gT2f3Fe44

user189275

4:59 PM

Then read Lockhart.

@ArbitraryKangaroo does it work without sound? I'm at work

user189275

@Sconibulus: The "cc" at bottom are probably correct, I checked randomly, so you can watch without sound.

@ArbitraryKangaroo The "cc"?

closed captioning

@Sconibulus Oh, the captions. The subtitles. I see.

5:08 PM

that video was much less offensive

I forced myself to read a bit more of the paper, it seems like he has a fundamental misunderstanding of the difference between applied Maths and theoretical Maths

@LukasRotter i don't think anyone would call you out for not having the tag. If the code is self explanatory, then you don't need basic computer knowledge to figure it out

You absolutely need to know Arithmetic and basic Algebra to be a functioning member of society, and that is what is taught in Primary and, to a lesser extent, Secondary school. Much as you need to be able to understand tonal differences to be able to conduct a spoken English conversation with any degree of grace

At least in my experience, upper level topics such as Geometry and Calculus DO start with some very basic expressions, and all theorems are built up from there in much the way he says they should be

but those aren't required in day-to-day life by the vast majority of people, and so most people don't take those classes

Yes, you need the results of them for something like an Engineering degree, but most people don't have those

user189275

@Sconibulus: I disagree. I completely agree with Lockhart and the dialogue in pages 6~7 . Also, from a interview, "Aside for practical applications like tipping and balancing checkbook why do we need to learn math?

We don’t need to learn math, any more than we need to learn poetry and music. As for the practical world, arithmetic procedures are mechanizable. All you really need is a good sense of estimation and the ability to use a calculator. I teach third graders to use a calculator and balance a checkbook. We should not be training children to be arithmetic machines. We build calculato…

user189275

abettereducation.blogspot.in/2009/06/…

Arithmetic is to maths as those tonal differences are to music, pretending otherwise is a disservice to Maths

yeah, that shows his lack of understanding of the fundamental differences between Applied Maths and Theoretical Maths

People need to understand concepts as Rent is 600$ a month, I make 10$ an hour, I work 30 hours a week, how much will I have left over as discretionary each month

it's pretty vital

as is knowing whether someone is shouting at you, or asking a favor

the difference is, our brains are wired for social situations, so most people can pick the latter up without having any sort of official teaching for it

(although a class like that for autistic people is sounding like a really good idea, now that I've articulated it)

5:27 PM

@Sconibulus, you are practically self-learning that as a baby - this is one of the methods for a baby to actually pick up information and start comprehending words.

Would it be possible for you to edit this answer to explain how you reached this conclusion given the information in the question? (A lot of explanation can be taken from the comments, if someone has the time to do this.) — rand al'thor Mar 8 '15 at 12:50

Two answers here need editing to add explanation.

@ArbitraryKangaroo Lockhart does maths teachers a disservice. He accuses them of teaching the formula for a triangle's area without giving any justification or proof of it or insight into why it might be true. A maths teacher absolutely should teach the formula, so that students can use it later, but (if a good teacher) will teach context as well.

I feel students would do better if they understood where all these formulas came from instead of just being fed the formulas on a piece of paper and told to memorize them. Especially in higher mathematics(algebra 2 and geometry), no one really(in my experience) explains how to find the area of a circle or why the volume of a sphere is what it is

isn't that what Radians is all about, which you were complaining about earlier?

Lockhart bitches about notation -- thinks teachers teach too much needless notation. sec x? OK, we don't need sec, but there are worse obstacles in learning maths than the name of this function which isn't used much anyway. Referring to lines as e.g. AB and CD? Isn't that actually simpler than his allegedly simple names "line 1" and "line 2"? And we might use l_1 and l_2 instead -- which he doesn't acknowledge.

And in the context of geometry, if you need to refer to a line, there are usually two pertinent points on it, so his "random and irrelevant points" bitch is unfair, I think.

I don't get his remark about the overline over AB. Isn't that for when you want to refer to the vector AB rather than the line? And mathematicians don't write m∠APC, we write ∠APC with no m.

5:38 PM

@Areeb I think the volume of a sphere proof was in youtube. It does not take a whole lot to just search a few stuff in google if someone is really interested to know

the volume of a sphere proof I remember off the top of my head involved integrating the area of the circle

so I get why I wouldn't have learned that in my Geometry class

there's probably another one I did learn, I don't remember questioning it

@Areeb I was never good at remembering all these formulas and stuff. Once, I have proven a theorem on an exam in school. I simply didn't remember it was a theorem. My teacher was very surprised.

@Areeb Not sure what's the best way to teach the area of a circle if calculus hasn't been covered yet. You can draw pictures of a circle cut into 2n sectors, which are then arranged alternately point-downwards and upwards so it looks like a πr by r rectangle, but proving it.....

There was the Archimedes proof for the Area of the circle..

Q: Visually stunning math concepts which are easy to explain

@RosieF I found a really simple proof which involved turning the circle into a triangle and it only used basic knowledge about triangles and the diameter of a circle

user189275

5:42 PM

I don't know what's the point of not doing circle proof without using calculus. The unwrap circle proof is good, and you can find several ones at:

user189275

746

Since I'm not that good at (as I like to call it) 'die-hard-mathematics', I've always liked concepts like the golden ratio or the dragon curve, which are easy to understand and explain, but are mathematically beautiful at the same time. Do you know of any other concepts like these?

soft-question education big-list

@Sid yeah it's easy to find but it wouldn't be hard to teach in class

@ArbitraryKangaroo What if students who haven't been taught calculus yet need to know it?

user189275

@RosieF: That's my point. Any student can intuively understand the unwrap proof without being exposed to calculus formally.

user189275

And a smart enough can figure it by own.

5:44 PM

@RosieF you don't need calculus for the unwrap proof

user189275

@RosieF: See 152 times upvoted answer on that MSE question.

That's circumference though, not area

user189275

@Sconibulus: What is what ?

user189275

See the comments too.

the only thing I see on there that looks anything like 'unwrapping' with circles

user189275

5:46 PM

What ?

user189275

Really, aren't you telling riddles ?

I would post a photo of the proof if I wasn't on mobile

user189275

@Areeb: Which proof ?

@ArbitraryKangaroo I share Nicholas Wilson's skepticism. The diagrams are pretty, and the results they suggest happens to be true, but that is no proof. Link: math.stackexchange.com/a/743459/344044

5:47 PM

you could just link to the actual answer you're talking about... I thought you were talking about this one: math.stackexchange.com/a/738749

I found it on betterexplained.com its the unwrap proof

Also, both of those look a lot like Delta Epsilon proofs

which is Calculus

Also, Calculus is not taught to kids. You can't possibly teach them the Volume of a sphere(for example) without teaching Calculus.

user189275

@Sid: Back in Archimedes' days ... calculus wasn't there ... but volume of an sphere was.

@ArbitraryKangaroo Standards of proof weren't as high

user189275

5:56 PM

I don't know. I never read the original pieces, I can't answer.

They used cylinders, cones and hemispheres and whatnot to show that.

AGain, the proofs were based on certain assumptions..

I still feel that's better than memorizing an equation that has no meaning

@Areeb But the equation does have a meaning. The teacher will have taught the meaning. And also proved it -- so that you can see that it isn't arbitrary.

user189275

6:12 PM

@RosieF I don't know if your last two sentence is applicable everywhere.

Okay regarding my casino puzzle, new ETP: Monday

I can say it is almost definetely Monday

Yey

:)

Or maybe Sunday if I'm lucky

We'll wait as much as it takes

user189275

@BeastlyGerbil: What is the puzzle ?

6:17 PM

@ArbitraryKangaroo, I've been working on a puzzle for a couple of months : meta.puzzling.stackexchange.com/questions/5528/…

@MariaDeleva, I don't think you have much choice regarding that anyway :P

@BeastlyGerbil I can come and beat you or tickle you :P Just joking of course :)

f" has disappeared and Gamow was suspended for multiple intentional plagiarism and sockpuppetry

@ArbitraryKangaroo, well f" has for some reason stopped coming to the site and sockpuppetry is when you create a fake user to upvote your own posts

I wouldn't bank on f'''s disappearance. It hasn't been that long since they were around; they might pop back in and post more answers any time.

Don't know he hasn't told us, may be a personal or family issue and he'll come back in a few months hopefully

Q: What's the policy about having multiple user accounts?

Sockpuppet (Internet)

A sockpuppet is an online identity used for purposes of deception. The term, a reference to the manipulation of a simple hand puppet made from a sock, originally referred to a false identity assumed by a member of an Internet community who spoke to, or about, themselves while pretending to be another person. The term now includes other misleading uses of online identities, such as those created to praise, defend or support a person or organization, to manipulate public opinion, or to circumvent a suspension or ban from a website. A significant difference between the use of a pseudonym and t...

26

Take this example: all SO user accounts of user known as "icepax". I can imagine of any human reasons to create a new user account at SO, e.g. willing to restart with a clean (reputation) history. But particular this one is extreme. The user known as "icepax" currently already has 10 accounts, e...

discussion etiquette users multiple-accounts

user189275

6:32 PM

Repeating a previously asked question: Anybody knows where I can find online 3d model of the are around Kryptos sculpture ?

@RosieF no one showed me what the equation meant

7:24 PM

Well, well. I've earned more rep here in the last month than anyone else except @GarethMcCaughan has earned in the last 3 months :-D

@Randal'Thor nah, Deusovi's got you beat too

7:49 PM

@Sconibulus I'm seeing 6627 (me) vs 6624 (Deusovi).

user61230

I win. I don't know what the competition is, but I win.

2

@Randal'Thor When I click 'Month' you've only got 6066

The competition is how many rep points could one win in a millenium :)

@Sconibulus Oh right, I must have picked up a few drive-by upvotes in July and August.

Correction: I've earned more rep here in the last quarter than anyone except Gareth, despite only being active for the last month of that time.

So you have been slacking before? :P Just kidding :) I guess people love you.

7:57 PM

@Sconibulus :) "Only" for 6066 points in 30 days.

he's clearly speeding, that averages 202.2 points per day, and the speed limit is 200. I'd write him a ticket, but the boss said that's only to be done if people are speeding by 5 or more, 10 if I want to be safe

2

...although I don't think he expected me to catch them with the Mean Value Theorem

2

GentlePurpleRain

8:21 PM

Good work, Puzzling! Duplicate question closed after only 13 views: puzzling.stackexchange.com/questions/43510

That hardly counts, we had moderator help :)

GentlePurpleRain

@Sconibulus In that case, my vote was no more significant than any other.