Mathematics - 2013-03-23 (page 1 of 2)

Charlie

12:02 AM

@Karl'sstudents :)

Karl's students

@Charlie I was busy for answering this: tex.stackexchange.com/a/103876/19356

Charlie

@Karl'sstudents geez!

@Karl'sstudents good!

Karl's students

@Charlie Thank you!

Charlie

@Karl'sstudents :D

@Karl'sstudents why "Karl"?

Karl's students

@Charlie Because of .... wait .... I will show the link.

Charlie

12:13 AM

@Karl'sstudents ok :)

Karl's students

Because I "hate" Karl's students:

4

A: What are the advantages of TikZ/PGF over PSTricks?

One good feature of TikZ is that the canvas size is automatically provided. In PSTricks, the canvas must be calculated manually to let TeX provide the required space (because TeX has no knowledge about PostScript). The TikZ documentation is extremely detailed. In the tutorial part, it even came ...

Charlie

@Karl'sstudents hahahah cool! funny

caveman

@Karl'sstudents, this is very good find

Charlie

@caveman why caveman?

@Karl'sstudents I'm Charlie because of this

Karl's students

Thanks @caveman and @Charlie!

caveman

12:18 AM

I created a tex account to upvote it

Charlie

Hi @tim

@Tim

Karl's students

@caveman Thank you!

Charlie

They won't change Stack exchange to Easter?

Won't we have easter eggs?

Charlie

12:50 AM

@Gasper ?

Gustavo Bandeira

1:09 AM

The problem is of course that without a giant on whose shoulders to stand, one may not reach very high. But logic, axiomatic, elementary number theory and so on might "easily" be rediscovered on one's own. I do not recommend that, however, as a good way to start researching math, for example you will have totally dfferent nomenclature and symbolism for well-known things, which will make communication difficult. — Hagen von Eitzen Feb 9 at 8:06

Charlie

@GustavoBandeira legal

Karl's students

@Charlie OK

Gustavo Bandeira

@Charlie Sim.

@Charlie Tá bem? Se resolveu com o caveira?

Charlie

@GustavoBandeira hehehe sim

Gustavo Bandeira

@Charlie Ontem aconteceu um evento bizarro.

Charlie

1:17 AM

@GustavoBandeira o quê???

Gustavo Bandeira

@Charlie O anon perguntou o que é first order logic. Pra mim.

Eu fiquei: "Como assim cê tá perguntando isso pra mim?"

Eu nem arrisquei dar a pouca definição que eu tenho, vai que eu estrague tudo e acabe emburrificando o cara.

Charlie

@GustavoBandeira HAHAHAHHA

Gustavo Bandeira

O Ethan me perguntou o que eram tabelas verdade.

Também achei estranho.

Charlie

@GustavoBandeira POOOXA

Gustavo Bandeira

Ainda é estranho pra mim quando eu sei de alguma coisa que esses caras num sabem.

Eu pude responder ao Ethan pelo menos.

28

Q: Life without DNA?

I'm by no means an expert in the field, merely a curious visitor, but I've been thinking about this and Google isn't of much help. Do we know of any lifeforms that don't have the conventional double-helix DNA as we know it? Have any serious alternatives been theorized?

dna

Arsênico?!

Karl's students

1:29 AM

--- Sexology -- — Karl's students Jan 7 at 1:24

Charlie

@Karl'sstudents hahahahahahahhah

Karl's students

@Charlie :-)

Charlie

@Karl'sstudents that was funny

Karl's students

@Charlie I mainly use PSTricks for drawing in my sexology major. :D

Charlie

@Karl'sstudents are you kidding?

Karl's students

1:33 AM

@Charlie Yes. I am kidding you!

Charlie

@Karl'sstudents :-|

@Karl'sstudents @gustavo Bye, I gotta go! have a good day!

Karl's students

@Charlie Sayounara!

Charlie

@Karl'sstudents Tchau tchau!

Peter Tamaroff

2:29 AM

@seaturtles @anon Now I can torment you twice as much!

Karl's students

4:40 AM

The last message was posted 2 years ago.

Gustavo Bandeira

4:52 AM

@Karl'sstudents Hello!

Karl's students

@GustavoBandeira Hi, please wait.... I am tooth brushing....

Gustavo Bandeira

Oky.

Karl's students

5:09 AM

@GustavoBandeira Finish, clean, and fresh!

Gustavo Bandeira

You took all this time to brush your teeth?!

Karl's students

@GustavoBandeira Yes.

Is it too long?

Gustavo Bandeira

I guess so.

Do you use braces?

Karl's students

Brushing, flossing, rinsing

@GustavoBandeira Yes.

I also brush my tongue .

Gustavo Bandeira

Me too, but I do it in less time.

I guess that's because of the braces.

Karl's students

5:17 AM

@GustavoBandeira: Did you purchase Mathematica?

κρανίοπεριπολία

2 years later...

1 year later...

Gustavo Bandeira

@Karl'sstudents Yes. Why?

Karl's students

@GustavoBandeira You are a rich guy!

This comment was removed because it violated our Terms of Service

or

This comment was removed because it violates our Terms of Service

?

κρανίοπεριπολία

The former.

Karl's students

@κρανίοπεριπολία OK.

Gustavo Bandeira

5:37 AM

@Karl'sstudents I am?

Karl's students

@GustavoBandeira Purchasing Mathematica is a big problem for me. :D

Gustavo Bandeira

@Karl'sstudents Why dont you use sage? Or scilab?

Karl's students

@GustavoBandeira Mathematica is much much better.

Gustavo Bandeira

But it's not free.

Karl's students

@GustavoBandeira How much did you purchase it?

Gustavo Bandeira

5:49 AM

It's better, but will you use this "better" someday?

I mean, Rolls Royce is better. But it's damn expensive, so I just need a car that is able to transport me by points in my city and this car should also protect me from rain.

I purchased through the university.

@caveman I like, I just don't have much to talk - I'm usually afraid of saturating chat users by overloading them with questions about math.

@Karl'sstudents I'm suggesting this to you because I make music with computer sequencer sotwares. I use FL Studio: They say Cubase, Pro Tools, Sonar, Logic,etc are better. But it's kinda lame, I tried to use these "better" software and I still could do much more with my shitty FL Studio.

BTW, in the mentioned softwares, the "better" is just about recording stuff - something I rarely do, FL studio still owns when it comes to MIDI editing and composing.

Karl's students

@GustavoBandeira OK. Rolls Royce is a car company?

Gustavo Bandeira

I guess so.

Bizarre. When faced with doubt, my certainty evaporates. XD

rolls-roycemotorcars.com

Karl's students

6:05 AM

@GustavoBandeira Done!

Gustavo Bandeira

@Karl'sstudents Dude... rolls-roycemotorcars.com/andtheworldstoodstill

I need only few things in my life:
-Be a brilliant mathematician;
-Be rich;
-Have a Rolls Royce.

Karl's students

@GustavoBandeira have a beautiful wife?

3 years later...

Gustavo Bandeira

I already have. =)

Karl's students

@GustavoBandeira i see.

Maybe need more :D

Gustavo Bandeira

More wives?

Look:

2

Karl's students

6:27 AM

@GustavoBandeira Oh my ghost!

Gustavo Bandeira

@Karl'sstudents What?

Karl's students

@GustavoBandeira Not safe for work.

Gustavo Bandeira

What you mean?

►

@κρανίοπεριπολία Kakka Krappy Party.

Karl's students

@GustavoBandeira The picture is not safe in public working environment. :D

Gustavo Bandeira

Why? Will people on MSE kidnap me?

κρανίοπεριπολία

6:42 AM

Demon Kakka

, previously known as , is a Japanese musician, entertainer, journalist and sumo commentator. He is the frontman of the heavy metal band Seikima-II, and is known for always working entirely in character. Biography Demon attended Toin Gakuen High School and graduated with honors from Waseda University with a degree in social science. His elder sister, Yumiko Kogure, is a former Tokyo Broadcasting System newscaster. In December 1982, he and Damian Hamada formed Seikima-II. In accordance to their "prophecy" and after completing their "world conquest", the band disbanded at the end of th...

Karl's students

6:54 AM

@GustavoBandeira No. It should not be meant like that.

Showing such a picture in the public makes others look at me strangely. :D

Gustavo Bandeira

But they're not looking at you.

They're looking at a virtual representation of you.

@κρανίοπεριπολία Sources: 1 2

Karl's students

The following must be pinned forever...

50 mins ago, by Gustavo Bandeira

2

user19161

9:59 AM

@GustavoBandeira Wow, I am happy for you!

κρανίοπεριπολία

10:21 AM

$\Huge\text{(}$removed$\Huge\text{)}$

伟轩

11:03 AM

@anon I don't understand Zhen's comment [here]( math.stackexchange.com/questions/338614/…)

user19161

11:22 AM

@伟轩 Hey Ben, why did you use that pic?

awllower

@伟轩 Now I want to make an "ansatz" that you can speak German!

Leong Lyn

11:54 AM

hello, does antone knows how to integraate this: sinxcosxsqrt(sinx)

Dominic Michaelis

12:19 PM

you know that sin'(x)= cos(x) dont you ?

伟轩

@JasperLoy Why not?

user19161

@伟轩 Haha, you're nuts!

伟轩

@awllower No. 我不胡说德国华

@JasperLoy Why not? I respect him very much.

user19161

Wow, it is really quiet on the main site. I posted an answer long ago but still no votes...

伟轩

@JasperLoy 你不喜欢安華？

user19161

12:28 PM

@伟轩 I don't know anything about him, so I cannot say anything.

Dominic Michaelis

@jasper huhu and wtf? whre did you got a chinese keyboard from ?

伟轩

@JasperLoy Bullshit of course you know about him.

user19161

@DominicMichaelis I did not get a Chinese keyboard!

user19161

@伟轩 I am not in touch with worldly affairs.

伟轩

@JasperLoy For me he is the last chance that that country has to become better.

Dominic Michaelis

12:30 PM

@伟轩 copy and paste ?

伟轩

@DominicMichaelis No I have a chinese keyboard on ubuntu

as well as french.

@DominicMichaelis Tu peux parler le français?

Voyez là, je peux taper en français.

Dominic Michaelis

nope only german, english and a bit latin

伟轩

Avec les accents.

c'est nul...

Goddammit if the OP wants to prove that the vanishing locus is affine then accept my godamm answer

user19161

@DominicMichaelis When did you learn Latin?

伟轩

@JasperLoy Sebagai orang singapura, kamu seharusnya tahu tentang apa yang berlaku di sekeliling nusantara

user19161

12:36 PM

@伟轩 Haha, I don't know Malay...

伟轩

@JasperLoy Ok, lu si hokkien lang, tio boh?

user19161

@伟轩 No, but I know Hokkien.

伟轩

@JasperLoy Which language do you want me to type in? :D :D :D

user19161

@伟轩 English. =)

伟轩

@JasperLoy Lu eng kai chai ti chui si an hua.

user19161

12:37 PM

@伟轩 HAHAHAHA

伟轩

@JasperLoy Well what do you expect me to type in?

There is no pinyin for hokkien.

user19161

@伟轩 Anyway, would be nice if you change into another pic, but it is your choice.

伟轩

@JasperLoy Why should I change?

user19161

@伟轩 Just weird that you have a politician as a pic.

伟轩

@JasperLoy I want to let the world know about him.

user19161

12:40 PM

@伟轩 OK, if there is only one man I want the world to know about, it is the Buddha.

伟轩

Right. But your attitude right now of renouncing the world is tantamount to escapism

Running away from one's feelings is not the solution

user19161

No, I just don't like to read the news.

伟轩

Fine then.

user19161

Hey, stop passing judgment on me based on limited info.

伟轩

ok.

user19161

12:41 PM

Anyway, my Chinese is quite bad, how do you read the second character?

伟轩

xuan.

user19161

Di ji sheng?

伟轩

huh?

user19161

Which tone I mean?

user19161

Ni wei shen me ting bu dong di ji sheng?

user19161

12:43 PM

Ni de han yu pin yin hen cha!

user19161

Ni de cuo, wo de dui!

伟轩

I will change the pic now

@JasperLoy Done.

user19161

@伟轩 Need to wait a while to see.

伟轩

@JasperLoy go to main site

user19161

@伟轩 Who is that?

伟轩

12:49 PM

@JasperLoy 天主你不知道那是谁？

user19161

@伟轩 No. Which monk?

伟轩

OMG

user19161

Grothendieck! Hahaha!

user19161

I thought of it after your OMG.

robjohn

@伟轩 ?

伟轩

12:51 PM

@robjohn yes?

robjohn

@伟轩 It vanished... :-p

伟轩

@robjohn what vanished?

user19161

@robjohn Just like Grothendieck!

robjohn

@伟轩 when I first read it, I read it as sake the drink :-)

伟轩

@robjohn god

user19161

12:53 PM

@robjohn WTF!

伟轩

@JasperLoy can you see it now?

user19161

@伟轩 Chat still has Anwar, but I see it on main of course.

robjohn

I saw: "Alexander Grothedieck for f**ks sake" and wondered why Grothedieck would do that to a drink... much less how.

伟轩

@robjohn I should go now. Really tired.

robjohn

@伟轩 later

In answering a question this morning, I came across nice proofs of $\int_{-\infty}^\infty\frac{\sin(x)}{x}\,\mathrm{d}x=\pi$ and $\int_{-\infty}^\infty\frac{\sin^2(x)}{x^2}\,\mathrm{d}x=\pi$

not using contour integration and only very tangentially related to Fourier series

Charlie

1:35 PM

@κρανίοπεριπολία I Sskull

I mean Hi

How sexy, jasper speaking chinese

Dominic Michaelis

@Jasper in school

Charlie

Hallo @dominic

Dominic Michaelis

@Charlie huhu charlie

Charlie

Wie gehts?

Dominic Michaelis

i am so pissed from the way they corrected my complex analysis exam

Charlie

1:46 PM

@dominic wie gehts is nicer than wassup

@DominicMichaelis oh!

Dominic Michaelis

from example there was a 4 point question to determine the singularities of $$\frac{\sin(z)}{z^2+1}$$

i said the poles are $i$ and $-i$ both are poles of order 1 as $z^2+1=(z+i)(z-i)$

Charlie

: /

Dominic Michaelis

they gave me only 1 point, because i didn't mention that $\sin(i)$ and $\sin(-i)$ aren't zero

Charlie

@DominicMichaelis :(

Dominic Michaelis

as i did later calculate the residues i thought i don't need to mention that they are really poles

for gods sake are those guys totally brain dead?

Charlie

1:52 PM

@DominicMichaelis relax, Dommy

Dominic Michaelis

and in ode they told me my ljapunov function "can't work at all" but it did and i proved it to them, argh i am so angry

Charlie

@DominicMichaelis you know you're right

Dominic Michaelis

we did have a gradient system and normaly you use the potential for the ljapunov function, as the scalar product worked to I took it because it's neater as i don't need to calculate the potential at all

and those stupid guys just put a question mark behind my solution ...

Charlie

Omg!

Dominic Michaelis

"in gradient systems the only possible ljapunov function is the potential" i got as an answer when i asked why they gave me no points, but that is obviously just bullshit

Charlie

1:58 PM

@DominicMichaelis oh!

Dominic Michaelis

if the potential doesn't work you won't find any other which work but if the potential works, it has absolutly no guarantee that it is the only one

Charlie

: \

Dominic Michaelis

2:14 PM

\[ a\]

why does it need a double blackslash

Charlie

:)

Dominic Michaelis

@awllower huhu and btw it is "Ich werde immer mein Leben lieben."

Charlie

@DominicMichaelis hahaha great !

Charlie

2:40 PM

:'(

awllower

@DominicMichaelis Oh
Vielen Dank.

Charlie

@Karl'sstudents hi!

hhh

I am looking for the complex parametrization of the airplane wing, can someone remember it? Was it doen with Rieman-zeta?

Charlie

All by myself, I don't wanna be all by myself

@hhh oh

Karl's students

2:57 PM

@Charlie: hey folk!

Charlie

@Karl'sstudents hi Karly, how are you?

Karl's students

@Charlie while(true){Console.WriteLine("I am fine!, and you?");}

Charlie

@Karl'sstudents I'm fine too :)

Karl's students

@Charlie: have you starred this comment? chat.stackexchange.com/transcript/message/8647552#8647552

Charlie

@Karl'sstudents no I did not

Karl's students

3:05 PM

@Charlie Please do it for me. :D

Charlie

@Karl'sstudents oh, why, dear?

Karl's students

@Charlie Because it is fun!

Charlie

@Karl'sstudents oh, I did not think....

Karl's students

@Charlie Oh my ghost. Apparently we have different tastes.

@GustavoBandeira: I will frame your photo to have mathematical sense.

Charlie

@Karl'sstudents :) but I like you anyway

Karl's students

3:09 PM

@Charlie I love you! :D

Charlie

@Karl'sstudents aaaww thanks you made my day! :D

Karl's students

@Charlie I love Jasper Loy too. :D

3

Charlie

@Karl'sstudents great!

awllower

I am wondering, if Alexander Gruber will show up, when we start discussing group theory?

Charlie

@Karl'sstudents now its starred :D

Karl's students

3:19 PM

Batman is coming...

The code is given as follows,

\documentclass[pstricks,border={-8.5mm -5.5mm -8.5mm -5.0mm}]{standalone}
\usepackage{pst-eucl,graphicx}


\psset
{
    runit=\psunit,
    fillstyle=solid,
    PointName=none,
    PointSymbol=none,
}

\pstVerb
{
    /theta 72 def
    /Major 6.0 def
    /Minor 3.3 def
    /p2c {dup 3 1 roll cos mul 3 1 roll sin mul} bind def
}

\def\DeclareNodes
{
    \pstGeonode
        (0,-8){Bottom}
        (0,8){Top}
        (0,0){center}
        (0,2.7){A}
        (0.5,2.7){B}
        (1,3.25){C}
        (1.2,1.3){D}

Charlie

@Karl'sstudents oh my ghost

@Karl'sstudents you liked that, huh?

Karl's students

@Charlie I like doing something fun but educational.

Charlie

@Karl'sstudents you're really good, like that Jasper loy flag you did :D

Karl's students

3:34 PM

Hopefully Gustavo likes this chat.stackexchange.com/transcript/message/8650043#8650043

Charlie

@Karl'sstudents ow...you did nothing to me :( :P

Karl's students

@Charlie Show your picture, I will frame it with another interesting curve.

Charlie

@Karl'sstudents oh noes!

Karl's students

I used Heart curve!

Nimza

Hello!

@Charlie good day!)

Charlie

3:44 PM

@nimza Hello, Leshetchka!

Nimza

I have an elementary question about tangent vectors to manifold, particularly coordinate transformations. Can anybody help me please?

If $\{x_{U}^i\}$ and $\{x_{V}^i \}$ are two coordinate systems in neighborhood of point $x$ then for any $X \in T_{x}M$ there correspond the uniqely defined coordinate vectors $\xi_{U}$ and $\xi_{V}$ in the above bases

Charlie

@Nimza :(

Nimza

@Charlie what?)

Charlie

@Nimza I cannot help you...

Nimza

oh(

Charlie

4:11 PM

@Karl'sstudents Do you know my name?

Karl's students

@Charlie no

Charlie

@Karl'sstudents Marília

Karl's students

@Charlie Oh... I see.

@Jasper otti: How are you?

Charlie

@Karl'sstudents whats wrong?

Karl's students

@Charlie Your name looks like female's name.

Nimza

4:17 PM

haha, captain detected

Charlie

@Karl'sstudents I'm

Karl's students

My name is Teoh Kee Kee.

Charlie

@Karl'sstudents you're serious?

Karl's students

@Charlie I am Jasper Loy's classmate.

Charlie

@Karl'sstudents really? You know him?

Karl's students

4:20 PM

@Charlie Yes. I know him.

Charlie

@Karl'sstudents cool!

Karl's students

@Charlie You know him as well?

Charlie

@Karl'sstudents unfortunately not

Karl's students

hi folks, do you know at what temperature the mosquitoes stop biting us?

Charlie

@Karl'sstudents you still love me?

Karl's students

4:24 PM

@Charlie Yes. I want to embrace you!

Charlie

@Karl'sstudents aaw how.cute! Me too

Karl's students

I am writing a free tutorial on PSTricks but I need some native English people to proofread it voluntarily.

Charlie

SKUUUULL!!

κρανίοπεριπολία

waaaazzzup?

Charlie

@κρανίοπεριπολία I'm fine, and you?

@Karl'sstudents ask Jasper

κρανίοπεριπολία

4:37 PM

fine thanks

Charlie

@κρανίοπεριπολία :D

κρανίοπεριπολία

;)

Matt N.

Hola chicos y chicas.

κρανίοπεριπολία

hi

hhh

Has anyone here idea how to parametrize airplane wing? I cannot easily here how to change this to make it realistic: i.stack.imgur.com/Xk98n.png. It should be tilted somehow like a water-drop.

Karl's students

4:45 PM

@Charlie It is a good idea!

@hhh It is hard to find the expression without some trial and error.

hhh

Looks a bit better but dunno how inside

amWhy

I've never seen this user post before...the user-name prompted me to check his/her profile: it's hard to reconcile the contrast...!

hhh

Got it a bit better :)

Nimza

@hhh why do you use this parametrisation? any reason?

hhh

It is wrong, poor parametrization -- there is a better air-drop design but cannot realize it now

Nimza

4:51 PM

via Jukovski function, right?

Chris's sister and pals

Hi. I wonder myself if $\sum_{k=1}^{\infty} \frac{1}{2^k k^2}$ might be compute elementarily without using the dilogarithm identities. Have you ever seen such a proof?

κρανίοπεριπολία

hi

Chris's sister and pals

Moreover, without touching integrals.

@κρανίοπεριπολία: hi

hhh

@Nimza Precisely

Nimza