Mathematics - 2012-09-24 (page 3 of 3)

Jonas Teuwen

22:07

Hello.

MeAndMath

Well guys...I'm leaving.Have a good night!!!

Jonas Teuwen

Good night.

MeAndMath

@JonasTeuwen Ngiht,Jonas!

Jonas Teuwen

@OldJohn I went to drink some beer at the chess club!

Old John

@JonasTeuwen wow - we must play chess sometime :)

Jonas Teuwen

22:08

@OldJohn I was there to drink beer!

@OldJohn The best player at this club is 2712... I believe.

A little boy.

Old John

@JonasTeuwen damn - too good for me

Jonas Teuwen

Or... he must be 18 or so already.

Old John

I once beat a guy who was about 2300 - but he was even older than me :)

Jonas Teuwen

@OldJohn I am weaker... at least like 500 points.

My friends are all >2300 8-(.

The ones that play chess.

Old John

I never took chess that seriously - but I was quite interested in endgame studies many years ago

Jonas Teuwen

22:10

Well, neither did I!

I just do something 8-).

Old John

@JonasTeuwen This was probably one of the first endgame studies I ever came across

user19161

@JonasTeuwen Isn't that like the top few in the world?

Jonas Teuwen

@OldJohn Oh yes.

@WillHunting Top 30 or so, yes.

user19161

@gustavo I see you have been talking nonsense with meandmath.

user19161

@OldJohn I was only interested in chess in school, took part in some competitions too.

Old John

22:19

I once played in a blitz tournament against Michael Adams - before he got into the top 10 in the world

Jayesh Badwaik

@OldJohn Oh wow.

Old John

@JayeshBadwaik but he was only 11 at the time - and beat me horribly :(((((

user19161

I admire Kasparov! After all, his name is a variation of mine. :-)

Jayesh Badwaik

@OldJohn Ohh! I cannot stop having a laugh now. sorry

@WillHunting I guess Kasparov is now arrested.

Old John

@JayeshBadwaik no problem!

user19161

22:22

@JayeshBadwaik For what?

shookees

Hi guys, what does this symbol "⊆" mean?

Jayesh Badwaik

@OldJohn :-)

user19161

@shookees It means subset of.

Old John

@JayeshBadwaik I did predict at the time that someday he would be a really good player (!!!)

Jayesh Badwaik

@OldJohn That is a positive!

shookees

22:23

@WillHunting thanks! :)

user19161

@JayeshBadwaik For what?

Jayesh Badwaik

@WillHunting There was a case of a band named "Pussy Riot" who did some parody about Putin.

They got arrested. Kasparov is political as you might know.

user19161

@JayeshBadwaik I don't know anything about him.

Jayesh Badwaik

He was a protesting leader outside the court. He got arrested too.

Its on wikipedia.

Old John

@JayeshBadwaik what really annoyed me during the game where he thrashed me was that (even in a blitz game against the clock) he spent most of his time looking at the ceiling!

user19161

22:24

@OldJohn He was thinking of FLT maybe.

Old John

then looked back at the board and made a crushing move :(((

Jayesh Badwaik

@OldJohn Hahaha.

user19161

@shookees Is that all?

Jayesh Badwaik

@WillHunting or abc.

Link

hey, what is an example of: postion of an object is positive, its velocity is negative and its accelration is postitive

user19161

22:26

You again!

Link

sorry

:D

phyiscs is hard though

user19161

@Link You mean displacement not position.

Link

no, i mean position

thats how it's phrased

user19161

Then that is a bad way to put it.

user19161

How can position be positive?

user19161

22:28

Displacement is the standard term in such matters.

Link

okay then

whats an example though?

user19161

If v<0, s is decreasing.

Link

yep

user19161

If a>0, v is increasing.

user19161

If you have a horizontal axis that represents displacement, then on this line, the object will start at the right of the vertical axis.

Link

22:29

okay

and the pseed gets smaller, while it accelrates

speed*

user19161

It will move to the left.

user19161

But it will move to the left slower and slower.

user19161

Done.

Link

okay

and it still has positive acceleration? how, why?

user19161

Simple if you truly understand.

Link

22:31

i don't..

user19161

Why is a>0? Because v is increasing as s is decreasing slower and slower!

user19161

Read what I wrote carefully.

Link

okay, so it moves to the left, but it moves slower each time

which means it has positive accelration!

thanks!

user19161

It moves to the left so s decreases.

Link

s=speed?

user19161

22:33

s=displacement.

Link

oh

okay

i get it now

also, is a speed vs time graph the same as a velcoity vs time graph?

user19161

No.

user19161

Speed is the magnitude of velocity.

Link

okay

user19161

However in simple treatments, speed can be negative too.

Link

22:34

k

user19161

It really is referring to the velocity.

user19161

And speed really is the magnitude of v so speed is non-negative.

user19161

And often s stands for displacement of the particle.

Link

okay

user19161

Done!

Jayesh Badwaik

22:36

QED.

Link

Hey, what does it mean when accelration goes from positive to negative? or vice versa?

user19161

Oh no!

Link

Because as I understand it, it would mean an object is getting slower, then speeds up?

or the other way

user19161

When a goes from positive to negative, it means velocity increases and then decreases.

Jayesh Badwaik

@Link It all depends on your co-ordinates. When you think in terms of speeds up or slows down, you are thinking in terms of speed, but that is incorrect. It is always in terms of velocity.

Link

22:41

so there is a change in direction?

Jayesh Badwaik

@Link Change in direction occurs only when velocity changes sign.

Link

hmm

Old John

@Link just imagine being in a car with your foot on the gas pedal (accelerating) - then you see a cat in the road and start braking - at one instant the acceleration was zero as it changed from positive to negative

Link

ahh

okay thanks, i think i get it

i'll go look up youtube vids to learn this better

user19161

@link If you really understand the mathematics, there is no problem at all. So understand the math first.

user19161

22:42

A good teacher will explain the math and everything is clear.

Link

mine doesn't

she started with graphs

:C

user19161

A bad teacher will give many examples without the math.

Link

mine....

user19161

The explanation could be in the graphs though.

Link

maybe

user19161

22:43

From my experience, most teachers are bad.

Link

yea

user19161

Often math teachers do not really understand the math themselves!

user19161

Sigh...

Jayesh Badwaik

I want to take some liberty here.

18 mins ago, by Link

phyiscs is hard though

user19161

Everything is hard.

Jayesh Badwaik

22:46

@WillHunting Wait for my full quote.

user19161

Even the janitor Will Hunting has a hard time cleaning the toilets at MIT.

Jayesh Badwaik

Physics is geometry -- Einstein.
Geometry is mathematics -- Me.

"If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is." --- John von Neumann.

user19161

@JayeshBadwaik Haha, OK. My life is very complicated now...

user19161

And that's another John!

Jayesh Badwaik

@WillHunting Mine too.

user19161

22:48

@JayeshBadwaik Hehe, we will share in future...

Jayesh Badwaik

@WillHunting Yup.

user19161

Let me tell you what my prof said.

user19161

Once we were discussing various branches of math.

Jayesh Badwaik

okay.

user19161

Then someone said this is interesting but that is not interesting.

Old John

22:49

My life has become much simpler since I retired: stay alive as long as possible, make the money last as long as possible, and enjoy everything :)

user19161

Then he said: Everything is interesting. Even cooking noodles is interesting.

user19161

End of story.

Jayesh Badwaik

QED.

user19161

@OldJohn The constraints of the system!

Jayesh Badwaik

@OldJohn Awesome. Actually, I recently had a very scary thought thinking about re-incarnations. I realized how thankful I was not to have any such memories carried about.

user19161

22:51

@JayeshBadwaik I call it rebirths.

Old John

@JayeshBadwaik memories of previous incarnations could get really tough to cope with

user19161

@OldJohn Unless one's life is already very tough in which case it could provide relief.

Old John

@WillHunting yes - basically maximisation subject to restraints!

Jayesh Badwaik

@OldJohn Linear Programming (approximately).

Old John

@JayeshBadwaik yep

user19161

22:52

@JayeshBadwaik There is nonlinear programming.

Jayesh Badwaik

@WillHunting I know. But, engineers do not like non-linear. They avoid it like bubonic plague. :P

user19161

I only know about...television programs, HAHAHA.

Jayesh Badwaik

Recently there was news on slashdot that facebook software is leaking your old private messages to the wall.

user19161

Hey @meandmath! I read your interesting conversation with gustavo...

Jayesh Badwaik

Hey @meandmath! I read your interesting conversation with gustavo...

JINX

user19161

22:57

@JayeshBadwaik Erm, that looks fake.

Jayesh Badwaik

@WillHunting Its not!

Now you have to do something I say.

Charlie

@WillHunting really?Gustavo...he's a little silly

@LInk

Link

yes?

user19161

@Charlie Yeah, he is just talking crap I know.

Charlie

was that exercise you asked right?

Link

22:59

which one?

Jayesh Badwaik

@WillHunting Charlie?? nvm...

Charlie

@Link physics..bouncing ball...

user19161

@JayeshBadwaik That means a name change.

Link

oh i got it

thanks

user19161

@charlie Haha, a name change!

Charlie

23:00

@Link oh..good!

@WillHunting yeah!

user19161

@Charlie I will be changing mine in 17 hours.

Charlie

@WillHunting I think Charlie is just fine

user19161

@Charlie Better name than meandmath.

Charlie

Will huntung is your favorite character...Charlie is mine

@WillHunting :D

user19161

@Charlie It is hard to type or read meandmath.

Charlie

23:02

@WillHunting yeah I realized

well,I would use "Charlotte"

but I like Charlie

Jayesh Badwaik

I am thinking of changing my name to Batman.

Link

....

Jayesh Badwaik

;-)

user19161

@JayeshBadwaik That is Jonas!

user19161

@Charlie I don't like Charlotte CHurch singing.

Charlie

23:04

@WillHunting yeah..me neither...that's why Charlie!I like to be called Charlie!

user19161

@link I expect a velocity question from you every day!

Jayesh Badwaik

@WillHunting Yup, I forgot. Hmm, well, then JackClawson. :P :P

math101

Is old John the big Saint here?

Jayesh Badwaik

aka Razor.

user19161

@math101 No he is just old John.

math101

23:05

ohhhhh lol

He just has a cool pic

Link

lol, but it is very confusing

user19161

You do calculus right @Link?

Old John

@math101 WTF is a big saint???

user19161

@OldJohn Maybe he means God.

math101

You seem to have saintly being

Saintly airs

Old John

23:08

@math101 Narh - just meant to be pic showing that I am actually quite old

math101

How old is quite old

Charlie

why my gravatar still showing the old name?

Old John

@math101 60+

math101

My granddad is 78 and is young chick

Not that old yet dont kid yourself

user19161

@Charlie refresh browser

Charlie

23:09

@WillHunting \o/

user19161

@Charlie QED.

Charlie

@WillHunting I'd like to talk more with you..but I'm in a hurry here... :(

damn...you read

I'm ebarrassed...

user19161

@Charlie Bye, I am off too. You can email me if you want.

Charlie

@WillHunting :-)))

Link

yes

@WillHunting, yea, i have calc

hey, on a postion vs time graph, direction is wheter the slope is positive or negative right?

user19161

23:31

@Link Again I am assuming that position means displacement which can be positive or negative.

user19161

@Link Ask yourself: what is the slope of a displacement-time graph?

user19161

You did calculus, you should know that.

Link

i'm in calculus

so starting a bit

user19161

Velocity is the rate of change of displacement with respect to time.

user19161

So the gradient of a displacement-time graph is velocity.

Link

23:39

gradient? slope?

okay

got that

user19161

Well, gradient means slope.

Link

k

user19161

What do you mean by direction above?

anon

anybody know if a maple 16 file can be opened and printed with maple 13?

user19161

No idea, sorry.

user19161

23:43

Actually @link later on you will learn that for example in three dimensional space, displacement, velocity and acceleration are all vectors. But for now, one only talks about motion along a line, so one uses negative, zero, or positive real numbers to denote these quantities.

user19161

One then has to show that the two ideas coincide in the elementary case.

Old John

@WillHunting I am very confused by your gravatar at the moment - on my screen I keep seeing 2 different versions ?!?!

user19161

@OldJohn Sure? It has been like that for days!

user19161

@OldJohn Try refresh!

Old John

tried that earlier

user19161

23:47

Haha, mysterious things always happen to me...

user19161

@OldJohn You see the blue square and the purple default ones?

Old John

@WillHunting yep - both on screen at the same time

user19161

I am quite sure nobody can guess my password.

user19161

It is ************.

Old John

do you want a screenshot of what I see?

@WillHunting ROFL

user19161

23:48

@OldJohn Not needed, but you can if you want.

user19161

@OldJohn Of course, I was using algebra there.

Old John

@WillHunting Narh - I am sure you can visualise what I see - and I need to sleep very soon

user19161

@OldJohn Yes, go to bed you!

Old John

@WillHunting I take that as an admonition that my presence is no longer required :))))

G'night all

user19161

Ding ding ding!

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$Mathematics$ Mathematics