The h Bar

Some time ago I switched departments within the same institution. Before leaving I had an idea of a paper and started to work on it. I shared my thoughts on it with my then-coworkers and they praised it. So now, after I settled things in a new department, I continued to work on that paper and com...

lets see....

CooperCape

wow crazy

Anonymous

3:29 PM

@0celóñe7 I bought a Chegg subscription few weeks back. It's pretty good (as you had mentioned). They answer most questions within an hour. :) (Although the one-on-one tutoring prices are ridiculous :P)

AccidentalFourierTransform

@ACuriousMind that book is rather nice

the first chapter at least

Prathyush Poduval

@Blue Have any plans on sharing it like your etoos lectures? :P

AccidentalFourierTransform

thx 😊

Anonymous

@PrathyushPoduval Nah. It's very costly. Can't share. XD They only answer 20 questions a month per subscription. (Around Rs. 1200 per month)

Anonymous

Can't waste my questions :'D

Prathyush Poduval

3:31 PM

How are their textbook solutions?

Anonymous

But well, if you want textbook solutions I can send you snapshots

skullpatrol

60 rs/question?

Anonymous

Or a solution to a particular question...that too

ACuriousMind

@AccidentalFourierTransform I had no doubt about that

Anonymous

@skullpatrol Yeah. And including textbook solutions (for some books)

Prathyush Poduval

3:33 PM

@Blue Thank you very much, I'll ping you if I need any help :P

Anonymous

@PrathyushPoduval Okay. Hehe :P

Prathyush Poduval

You don't get it in pdf forms?

Anonymous

@PrathyushPoduval They are no fools :'D

skullpatrol

Team makes the dream come true guys.

0celóñe7

@PrathyushPoduval used book deals are like steam sales

impossible to resist

\$40 for a \$96 book

Prathyush Poduval

3:35 PM

@0celóñe7 Yeah, I'm going to buy used books in the future

skullpatrol

Brand new books are a rip off.

Prathyush Poduval

After finishing it, itl just stay there gathering dust

I like to buy only very good books brand new

AccidentalFourierTransform

@ACuriousMind you mad at me? :-(

what did I say?

0celóñe7

it sounds like you doubted him

ACuriousMind

@AccidentalFourierTransform Hm? Why does me having no doubt about Salmhofer's book being nice indicate I'd be mad?

AccidentalFourierTransform

3:41 PM

@ACuriousMind I wouldnt expect such a dry response from someone from Germany, that's all

0celóñe7

the germans are known for their high spirits and friendliness

Anonymous

Germans are known for their wet response? :D

ACuriousMind

::ahem::

0celóñe7

@ACuriousMind I have three flavors of lozenge

ACuriousMind

Great - any Ricola?

0celóñe7

3:43 PM

no, too much sugar

Anonymous

Is one them "mango? @0celóñe7 Give that to ACM

ACuriousMind

@0celóñe7 No such thing as "too much sugar" :P

My teeth shall die a sweet death

Anonymous

Don't forget @Mostafa's preachings

0celóñe7

@Blue do you know analysis of a real variable yet

Anonymous

@0celóñe7 I'm in the process of learning. Doing chapter 1 of Courant and John's

0celóñe7

3:46 PM

why not abbott

Anonymous

@0celóñe7 Our teacher is following C & J actually

Anonymous

So it will be easier for me to keep track

ACuriousMind

@Blue That didn't ping him because his name now has a bunch of weird stick-like symbols around it

Anonymous

Those sticks indicate the topography of his teeth I suppose :P

0celóñe7

Ew, I don't like the order of this book at all

Does it even have any topology?

Anonymous

3:47 PM

@ιllιlılMostafaıllııllıl

0celóñe7

650 pages!?!?!

Anonymous

@0celóñe7 It's an "introductory" book

Anonymous

@0celóñe7 I learnt Differential/Integral calculus in high school if that counts as real analysis XD

0celóñe7

I am weary of too much topology in a first analysis course

or do I mean wary

or wery

who knows

in any case, there needs to be some topology but not too much

Anonymous

Nah. It doesn't have topology :/

0celóñe7

3:50 PM

@ACuriousMind can I spoil pls

what are you gonna do if I drop the nuclear spoiler?

Anonymous

@0celóñe7 It has 2 volumes. The second one is over 1000 pages

Anonymous

The first one deals with single variable

0celóñe7

@Blue that is completely ridiculous

Anonymous

The second one deals with multivariable

Anonymous

Anyway, I don't have everything in syllabus

0celóñe7

3:52 PM

lol volume 2 is split into two books

Anonymous

Nor will I get enough time

Anonymous

@0celóñe7 well, true

Anonymous

hehe

0celóñe7

Ugh, many hundreds of pages for Riemann integrals

what a waste

ACuriousMind

@0celóñe7 Be very disappointed in you.

Anonymous

3:57 PM

@0celóñe7 I had a question about Taylor's theorem. Do the Cauchy and Lagrange's form of the expansion remainder differ in accuracy? Or are they equally accurate?

0celóñe7

Lagrange remainder is exact, no error

AccidentalFourierTransform

the error you make is independent of the form of the remainder you use

0celóñe7

pretty sure it's the same for the other

AccidentalFourierTransform

if you approximate $\sin(x)$ by $x-\frac16x^3$, the error will be $\sin(x)-x+\frac16x^3$, no matter what remainder you use

0celóñe7

@Blue Because of how it is derived?

@AccidentalFourierTransform this

the error simply equals the function minus the Taylor series with $n$ terms

the various "forms" give more or less convenient expressions for that

@BalarkaSen study group amazon.com/gp/product/1107021030/… ?

Anonymous

3:59 PM

Ok. So the value of error is same irrespective of the form of remainder. Gotcha. Yeah, the derivation seemed to say so. Balarka was saying something else which confused me. (Probably I understood it wrong)

Balarka Sen

@0celóñe7 how about no

0celóñe7

@BalarkaSen :(

@Blue I've never seen Cauchy's remainder used

Anonymous

@0celóñe7 Me neither

0celóñe7

Now the thing to keep in mind is that you don't know where the point you evlauate $f^{(n+1)}$ is at

in Cauchy's remainder there's another term that you have to evaluate at the unknown point

Balarka Sen

That's what I was talking about, I think.

0celóñe7

4:02 PM

that may or may not be beneficial

I can't imagine it ever being beneficial though

Balarka Sen

The error term is exact, but not efficient.

0celóñe7

@Blue Usually you justr pick the midpoint between $x_0$ and $x$ to evaluate at

Anonymous

@0celóñe7 Right, yes

Balarka Sen

I think if you plug in the mean of the interval endpoints in then Lagrange is always a better error than Cauchy.

0celóñe7

that should give an order of magnitude

@BalarkaSen but you wanted to learn $\epsilon$ measure theory

Anonymous

4:04 PM

@BalarkaSen What does "better" mean?

Balarka Sen

@Blue If you subtract off the error from the Taylor polynomial the absolute value of that is smaller than what you do with the other error.

Or at least, that is what I would expect.

0celóñe7

@ACuriousMind I will give you my HBO

Balarka Sen

Hm, or maybe you want to look at not a pointwise error but a mean or a standard error.

I don't really care tbh

Anonymous

Say f(x)=(blah blah) + error. You're saying |f(x)-(Cauchy's error)|>|f(x)-Lagrange's error| ?

Anonymous

I don't see how...

Balarka Sen

4:09 PM

Well, |f(x) - Taylor polynomial - Cauchy's error with c = midpoint of interval| and similar for the other term

and except that you probably don't want to say that for every x in the interval, but that integral of the square of that is greater than integral of the square of that for Lagrange

integrating for all x in [a, b]

aka "standard error"

Anonymous

@BalarkaSen Oh. That's ok. For a certain point in [a,a+h], Cauchy's error=Lagrange's error though

Anonymous

That may or may not be the mid-point

Balarka Sen

But you don't know that point, so knowing that such a point exists is not efficient.

You can't really use that fact to do any efficient approximation if you want to do it

Anonymous

Anyway, even if we take the mid-point, I don't see how you can always claim that is will be greater than the other...

Anonymous

@BalarkaSen Yes, got that

Balarka Sen

4:12 PM

I don't want to prove my claim. It's only what my intuition tells me, which might as well be not true.

Anonymous

What exam tomorrow btw?

Balarka Sen

None :) Day after tomorrow is physics.

we're free tomorrow, remember?

dmckee

@JohnRennie In addition to the occasional acerbic political cartoon he also did some really funny and well executed cartoons on adult subjects.

Anonymous

Oh. Then I'll ping you in the afternoon :D

Anonymous

Physics exam probably won't be much tough :P You can relax a day

dmckee

4:15 PM

I saw the book briefly at a cocktail party (at my parent's house, natch) and keep meaning to acquire a copy for myself.

Balarka Sen

@Blue Yeah hopefully. You can shoot a ping for sure

John Rennie

@dmckee ah, thanks, that looks an interesting avenue to pursue. Like many of my generation I grew up reading The Cat in the Hat and Green Eggs and Ham. But it hadn't occurred to me that Seuss did more adult stuff as well.

Balarka Sen

I am a bit queasy because I am not super comfortable with optics.

Anonymous

@BalarkaSen Which part of optics?

Balarka Sen

Say, refraction of light. We only have reflection/refraction

reflection is ez

dmckee

4:19 PM

@TheRaidersofLasVegas That may very well have been about "Stay out of it" political positions during the second world war effectively supporting the historical Nazis rather than connecting isolationism to white power in the way it reads this week.

But in any case, it skirts pretty near the line of disruptive political discussion. It it starts to generate trouble I'll trachcan it.

Anonymous

This has a good collection of questions based on refraction. Spend about an hour or two and I'm confident you'll master it. (Watch the ones in your syllabus if possible). @BalarkaSen

Anonymous

Sorry, it's this along with the one above

Anonymous

:P

Balarka Sen

@Blue Thanks a lot

I'll check them out if possible

Sid

WHat's the issue with refraction? I thought optics was one of the easier portions of high school syllabus

Though the thing I hate about optics is that you have to draw diagrams in that. Ugh

Balarka Sen

4:23 PM

The thing's I didn't spend much time on it. It was added to the pretest syllabus rather late.

Anonymous

Don't worry. Just watch the Refraction playlist. It's more than sufficient for any school test

ACuriousMind

@0celóñe7 I'm fairly sure they actually check whether I'm located in the US

0celóñe7

@ACuriousMind Do you have dual monitors?

ACuriousMind

@0celóñe7 yes

0celóñe7

@ACuriousMind Sometimes when I click on a program on the task bar or in search on the second monitor, it opens on the primary

is that normal?

ACuriousMind

4:28 PM

Yeah, programs deal pretty inconsistently with that

dmckee

4:39 PM

@0celóñe7 ::face palm::

In most X window managers it opens in on the current desktop and display unless you have bound it to some other space. That's the behavior I like and expect.

0celóñe7

@dmckee I don't understand, are you facepalming at me?

ACuriousMind

@0celóñe7 He's facepalming at Windows, I think

0celóñe7

It's inconsistent which is the issue

dmckee

Mac OS does a weird mixture. Most windows open in the current desktop and display, but if you open a file through the finder and the program is currently running and there are no windows for that program open on the current desktop, it will open the new one in the desktop where the program was launched. WTF?

@0celóñe7 I'm facepalming the windows behavior you just described.

0celóñe7

@JohnRennie How the heck have I managed to write 3TB to this 0.5TB hard drive in the two weeks I've owned it?

I didn't do anything with it since last night and somehow the total written has increased 200GB

John Rennie

4:49 PM

Hard work and perseverance? :-)

0celóñe7

@JohnRennie Uh. No.

The computer has not been touched since last night.

John Rennie

Are you going by the SMART counters?

0celóñe7

Samsung Magician has a counter, under which it states SMART

John Rennie

I suspect the counter is unreliable.

0celóñe7

Ugh, read speed went down by 1000

How is this happening

John Rennie

4:51 PM

You can use the Windows Performance Monitor to check what Windows thinks is being written to the disk.

0celóñe7

@JohnRennie it gives a history of what has been written to the disk over time?

@JohnRennie Is it normal for it to take ~3-4 seconds to open up the downloads folder? I only have 2GB in there.

John Rennie

@0celóñe7 I've just been looking at what counters Performance Monitor can track, and it only tracks bytes written per second not total bytes written. However you could leave it overnight logging the bytes written per sec to a file then the next morning numerically integrate the data.

Then compare this figure with what the Samsung Monitor claims.

0celóñe7

@JohnRennie It could be the benchmarks I'm running, but I have a hard time believing I wrote 200GB in one day doing benchmarks.

@JohnRennie But there is the mysterious 1000MB/s performance drop today

This is too stressful

John Rennie

200GB does seem a lot in a day, but then only you know what you've been doing with the PC.

ACuriousMind

It's probably part of a Russian botnet now :P

0celóñe7

5:01 PM

@ACuriousMind Why?

John Rennie

Read speed can be affected if something else is using the disk. Have you tried running Performance Monitor so see if there is any background disk activity?

ACuriousMind

@0celóñe7 That was a joke.

John Rennie

@ACuriousMind I told him not to boast about the new PC on Tor.

0celóñe7

@JohnRennie Indeed. Defender pops up whenever I run the mark.

It's not a large disk usage at all: 0.1MB/s.

ACuriousMind

@JohnRennie ¯_(ツ)_/¯

0celóñe7

5:02 PM

I'm not boasting, it's a piece of crap

dmckee

@0celóñe7 The OS will have a number of background processes that maintain databases used by the search engine and various programs may make occasional auto-backups, so you would expect some activity as long as you leave the machine running.

0celóñe7

Turning off defender does nothing

dmckee

On the other hand it is hard to see how that comes to 200 GB.

0celóñe7

@dmckee With an SSD those occur so quickly there's basically no disk usage when idle.

Oh, the 200GB is mysterious.

I have been running a lot of benchmarks, and if it's writing 1700 MB/s I can see that piling up.

ACuriousMind

Why are you running so many benchmarks?

0celóñe7

5:06 PM

@ACuriousMind I'm turning off potential issues --> run benchmark

and defender refuses to turn back on

welcome russian hackers

@JohnRennie Uhhh....I can't turn it back on

restarted and it didn't come back

ACuriousMind

It's ded

RIP 0celo7's computer

DanielSank

@EmilioPisanty finally, I have become relevant

1

Q: Lagrangian method for an LC-Circuit

In the paper http://physics.unipune.ernet.in/~phyed/26.2/File5.pdf, the author solves the LC-circuit using Euler-Lagrange equation. She assumes that the Lagrangian function for the circuit is $$L=T-V$$ where $T=L\dot q^2 / 2$ is the kinetic energy part and $V=q^2 / 2C$ is the potential energy...

lagrangian-formalism electric-circuits potential-energy hamiltonian-formalism hamiltonian

heather

hello

DanielSank

yo

ACuriousMind

@DanielSank You always were relevant <3

heather

5:14 PM

how goes it? @DanielSank

DanielSank

@heather sick

@ACuriousMind ehhh, perhaps. Someone asking about the Lagrangian of a circuit makes me really relevant though :-D

<3

heather

@DanielSank oh, i'm sorry, that's never fun

DanielSank

No, it's not.

ACuriousMind

@heather Depends on the medicine you get ;)

But yeah, generally not

heather

@ACuriousMind i feel like there's a reference here i'm missing...

DanielSank

5:16 PM

On the upside, I made oatmeal raisin cookies yesterday, and nobody else can eat them because they're infected >.>

@heather Nah he's just being goofy.

heather

oatmeal raisin?

DanielSank

yup

Best cookie.

heather

wrong, it's chocolate chip

or my mom's chocolate crinkle christmas cookies.

DanielSank

I will defend oatmeal raisin cookies to the grave.

ACuriousMind

Raisins, ew :P (I actually like raisins as such, but not in cookies)

DanielSank

5:17 PM

crinkle cookies are good too...

heather

@DanielSank ::shakes head:: i'm very disappointed

DanielSank

@heather, listen... oatmeal raisin cookies are amazing.

heather

they're okay, i guess.

DanielSank

chocolate chip cookies are also rather excellent.

heather

chocolate chip are much better.

DanielSank

5:18 PM

I propose that chocolate chip cookies and oatmeal raisin cookies live in harmony.

With plenty of either cookie for everyone.

heather

fair enough =)

DanielSank

What say you?

very good

heather

i'm hungry for cookies =)

DanielSank

Make cookies.

Take the butter out now so it's soft in a couple hours.

heather

hmm, i might just ask my mom if we can make cookies tonight =)

ACuriousMind

5:21 PM

Be a rebellious teenager and make cookies all on your own!

3

DanielSank

^

The trick is to learn all this stuff before going off to college.

AccidentalFourierTransform

@AsafKaragila For the sake of an answer assume monogamy and no homosexuality. — 123 8 hours ago

#NoContext

DanielSank

I arrived at Yale equipped to cook mujadara, baklava, chocolate chip cookies, oatmeal raisin cookies, and a variety of other essentials.

Saved my life.

heather

i can boil water and bake and use the microwave.

i also made some pretty good spiced apples once.

AccidentalFourierTransform

DanielSank

5:27 PM

@heather facepalm

Oh wait, you can bake. Never mind the facepalm!

:-D

Anonymous

I can only make instant noodles. :P

ACuriousMind

@DanielSank I arrived at uni never having really cooked because my mother has this thing where she intended to let other people cook and ends up cooking own her own anyway because she can't watch other people doing it "wrong" (such as using a different spoon that she would have used :P). I learned pretty quickly after some memorable salty noodles and a curry sauce that was inedible because it tasted purely like the spice.

heather

are dining plans not a thing in most colleges?

DanielSank

@ACuriousMind That is a very common kitchen phenomenon.

@heather Sure they are, but they don't always supply baklava and cookies.

heather

@DanielSank true

ACuriousMind

5:29 PM

@DanielSank The salty noodles or the obsessing over minutiae?

DanielSank

@ACuriousMind minutiae

AccidentalFourierTransform

and the salty noodles.

Balarka Sen

I can bake nonexistent noodles

Anonymous

@heather In my college most people eat hostel food only. Or sometimes from the canteen. But, in the long run no one likes to eat the monotonous hostel food.

heather

what i really need to learn how to make is my mom's meatballs

@Blue ah.

Anonymous

5:31 PM

Hostel Food=Rice/Roti+Veggies+Dal. Now repeat that every day, two times a day :'D

ACuriousMind

@heather The canteens are closed during the weekends (or at least on Sunday) here, so you're forced to supply yourself with food at least one day of the week

Anonymous

I'm lucky that my uni is close to my home. I can eat home food :)

Balarka Sen

How To Cook/Bake Fresh Air

►

ACuriousMind

Ah, yes, @BalarkaSen of course subsists on air and the tears of capitalists.

Anonymous

amazon.in/Food-Free-Last-How-Learned-Eat-ebook/dp/B00AEEBLO6

heather

5:36 PM

@Blue i do not know what to say.

Anonymous

It's worth buying

Secret

John Rennie

Should anyone be in need of culinary inspiration I am happy to offer my services as an expert in preparing some of the most appallingly fattening and unhealthy meals known to mankind.

Secret

We need a "How to bake pure olive oil"

ACuriousMind

@Secret No need to bake it, just drink it out of the bottle.

heather

5:39 PM

@ACuriousMind with this question you vtc'd as unclear, could you reopen/vtc as non-mainstream?

Sid

@Blue You forgot potatoes. :P

ACuriousMind

@heather I could, but why would I? It's still completely unclear how this thing with the other universes is supposed to work, in addition to it being a non-mainstream idea.

Sid

@JohnRennie You are the reason for the increased obesity in the world!!

Anonymous

@Sid You removed potatoes from the status of veggies? Shame :-)

Secret

lollol, so I must help decrease obesity then because I prepare raw veggies without any seasoning

heather

5:41 PM

@ACuriousMind but it's more primarily non-mainstream.

Sid

@Blue Potatoes is a special vegetable.

John Rennie

@heather I have to say it seems primarily meaningless to me ...

Anonymous

Well, that's true. Potato is the only vegetable which I like

John Rennie

@Blue Potatoes are uninteresting unless you fry them or add butter to them. In both cases any claim to a healthy diet the potatoes may originally have had is largely compromised :-)

ACuriousMind

@heather So? There's no obligation to choose the "most fitting" close reason, only to choose a fitting close reason. Besides, even if the displayed close reason wouldn't apply anymore (say, the question was now crystal clear but still non-mainstream), it would still be a waste of time to reopen it only to close it again. Sure, in this one instance it would cost me two clicks, but it would set a bad precedent potentially wasting the time of five reopen and five close voters.

heather

5:44 PM

@ACuriousMind ah, okay. Ignore me then =)

Sid

@Secret You are an early man? :P

Anonymous

@JohnRennie All tasty food is unhealthy. That's an inherent law of nature. The converse is not necessarily true. ;)

ACuriousMind

@heather Alrighty then

Secret

lol, I sometimes get too lazy to put salad dressing and sometimes cooking oil in my veggie

Counterexample: Most green veggie is very tasty even without flavorings

Anonymous

@Secret Not at all

Anonymous

5:46 PM

I hate all green veggies

John Rennie

@Blue though there isn't really such a thing as unhealthy food. It's just a question of how much of the food you eat.

Anonymous

I would never eat them unless my mom forced them down my throat

Sid

Green veggies are the healthiest thing out there. I started eating them after mid 9th grade

Anonymous

@JohnRennie Well. That's an addendum to the law. :P

AccidentalFourierTransform

except for lettuce

the worst food

not even food actually

Secret

5:48 PM

I actually like that bitter taste of brocoli

But celery? nope, it taste like plastic bag

ACuriousMind

@AccidentalFourierTransform Whaaaat? A nice Feldsalat with just vinegar and oil is pretty good

John Rennie

@AccidentalFourierTransform it killed the seven young Guinea Pigs!

AccidentalFourierTransform

Feb 8 at 21:37, by AccidentalFourierTransform

no taste, no texture, no nutrients

ACuriousMind

It appears the anglophone world is undecided on how to call the Feldsalat :P

Anonymous

@ACuriousMind with "vinegar and oil"! That's the important thing. With adding the right kind of stuff, everything seems tasty. For example I could deep fry any veggie with oil and it would taste quite good.

ACuriousMind

5:51 PM

@Blue I disagree, nothing will make brokkoli taste good :P

AccidentalFourierTransform

@ACuriousMind oh, we call those canónigos and they are the shit

Secret

I am fine chewing raw lettuce to the point my friend said I am basically a horse

AccidentalFourierTransform

those are not considered lettuce ffs

ACuriousMind

Discussing plants in other languages is weird. In German that is a kind of "lettuce" (= Salat)

AccidentalFourierTransform