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danielunderwood
danielunderwood
12:36 AM
@enumaris you're getting a MemoryError because you don't have this RAM
 
enumaris
enumaris
12:49 AM
@danielunderwood the MemoryError comes from vram
but I fixed it...
not really, I just used a different API that didn't cause a memory leak
 
danielunderwood
danielunderwood
1:09 AM
I'm sure you can find a similar golden bejeweled LED GPU
 
enumaris
enumaris
can't ssh into my gcp instance now to check on my results...
lol fail
 
 
2 hours later…
Sir Cumference
Sir Cumference
2:55 AM
Is condensed matter physics important for studying neutron stars?
 
enumaris
enumaris
uhmmm eh
not rly
neutron matter is pretty different than regular condensed matter...it's kept together purely by gravity
 
skullpatrol
skullpatrol
3:36 AM
confirmed by Wikipedia
> An abbreviated version of a quote by California politician Dianne Feinstein, from an interview with Cosmopolitan magazine in October 1985, on the topic of women running for public office. The original was: "... I really do have staying power. That's important for women who run for office. When you get in there and push for a lot of new things all at once and don't get them, you don't just leave.
> You have to commit, be a team player,*** learn the rules of the game. And then you have to play it better than anyone else.***"
Also see.
 
 
1 hour later…
PM 2Ring
PM 2Ring
4:54 AM
We've just had a visit from the father of antigravity. physics.stackexchange.com/a/484366/123208 I guess it'll be deleted shortly.
 
Secret
Secret
5:24 AM
physics in music structure
 
 
1 hour later…
Captain Bohemian
Captain Bohemian
6:47 AM
is there a concise name in physics for the position of a body as the function of time, which may be the solution of a set of equations of motion?
 
Sir Cumference
Sir Cumference
6:59 AM
@CaptainBohemian why not just "position"
 
Captain Bohemian
Captain Bohemian
@SirCumference because I want to emphasize it as the function of time.
 
John Rennie
John Rennie
@CaptainBohemian worldline? trajectory?
 
Captain Bohemian
Captain Bohemian
7:11 AM
@JohnRennie But I check the dictionary, which doesn't say the trajectory is the path as the function of time. I think worldline is better to be used in relativistic mechanics. I just want to describe the position of a heaven body as the function of time on the sky of earth.
 
John Rennie
John Rennie
I think most physicists would take the trajectory to mean the curve the object traces out i.e. $\mathbf x(t)$.
@CaptainBohemian astronomer's may have a preferred term for the position of astronomical objects. If so I don't know it.
 
PM 2Ring
PM 2Ring
7:56 AM
@CaptainBohemian The word "path" is fine for that. Or "apparent path". So we can talk about the apoarent path of the star Sirius as the Earth rotates. Or the path of the Moon around the celestial sphere over the course of a month. Etc.
Astronomers like to decompose the motion of a celestial object into its various components. The biggest component, the daily rotation of the celestial sphere, is also the simplest, so it's pretty boring. The Moon's motion is quite complex, and since its been the object of careful study for well over 2000 years several of the components of its motion have names. See Lunar Theory for a few details of this intricate topic.
BTW, dictionary makers are experts in language, they aren't physicists. They make an effort to accurately document how various experts use words in technical contexts, but ultimately, if you want to know what a word means in physics, consult a physics book or a physicist, not a general-purpose dictionary.
 
 
3 hours later…
PM 2Ring
PM 2Ring
10:43 AM
Fans of Derek Lowe may enjoy this article from a few months ago about a new synthesis for an oddly stable peroxide. It requires elemental fluorine, so don't try this one at home, kids. But I guess that's a little less scary than the original synthesis, which used our old friend chlorine trifluoride.
 
 
2 hours later…
user280247
12:14 PM
why $dq_{surr}=-dq_{sys}$? Is there a simple way to understand this? (q = heat, surr=surroundings, sys=system)
 
Ryan Unger
Ryan Unger
12:59 PM
@ACuriousMind it occurred to me that this is the wrong topology
there goes a week of work
 
Slereah
Slereah
1:27 PM
F
 
Emilio Pisanty
Emilio Pisanty
1:57 PM
any mods around? Why was my flag on this awful post declined?
why wasn't it left for the queue to handle?
@PM2Ring CC @JohnRennie
 
JMac
JMac
What did you flag it as that got declined?
LQP?
wait that's not even a flag, ignore my speculation
 
Emilio Pisanty
Emilio Pisanty
2:19 PM
@JMac NAA
eh, maybe it's not that bad, and it's just the last sentence that really sends it off track
heck, you know what, I'm just going to cut out that last bad part
 
John Rennie
John Rennie
2:39 PM
@EmilioPisanty I love his writing style :-) It's the little throwaway comments that make his article so entertaining.
 
Emilio Pisanty
Emilio Pisanty
3:00 PM
2
Q: Why are there $1/1.60217733 \times 10^{-19}$ electrons in a coulomb?

ipsa scientia potestasWhy that exact number of electrons in one coulomb? who decided it? there is nothing wrong with the number, it just seems slightly messy. Why didn't the scientific community just settle on an easier number, such as $1\times10^{-19}$ for example?

electrons charge conventions si-units metrology
hmmmm
where did OP get that figure?
it's waaay out
 
John Rennie
John Rennie
@EmilioPisanty that's correct isn't it? It's just the reciprocal of the electron charge $1.602 \times 10^{-19}$ coulombs.
 
user8718165
user8718165
3:54 PM
Hii @JohnRennie
@JohnRennie An object at rest in F moves at a constant velocity in frame F’. What does it mean? imgur.com/01JCSFe
 
Emilio Pisanty
Emilio Pisanty
@JohnRennie the figure is wrong. It's 1.602176634, not 1.60217733
 
John Rennie
John Rennie
@user8718165 suppose you are standing still holding an apple. We'll call your rest frame $F$. In this frame you are motionless at the origin and the apple you are holding is motionless. OK so far?
@EmilioPisanty I only remember it to 3 decimal places :-)
 
user8718165
user8718165
@JohnRennie yes sir
 
user280247
I don't understand what is heat :<
 
John Rennie
John Rennie
@user8718165 Now I'm cycling past you at 10 m/s. So in your frame I am moving with velocity $v = 10$.
 
user8718165
user8718165
4:05 PM
@JohnRennie yes sir
 
Emilio Pisanty
Emilio Pisanty
@JohnRennie sure
 
John Rennie
John Rennie
@user8718165 But I have a rest frame as well i.e. in my rest frame I (and my bicycle) are stationary. In my rest frame you and the apple are moving at a velocity of $-v$.
 
Emilio Pisanty
Emilio Pisanty
but it's weird that there's a figure floating out there that's so detailed but wrong
maybe it's in conventional electrical units?
 
John Rennie
John Rennie
@EmilioPisanty Googling it does find that figure for $e$ ...
 
Emilio Pisanty
Emilio Pisanty
@JohnRennie yeah, I know. It's weird.
btw @JohnRennie look what I attended last Sunday
 
John Rennie
John Rennie
4:08 PM
@EmilioPisanty cool :-)
You were at the wrong university of course :-)
 
Emilio Pisanty
Emilio Pisanty
I was at all the important Golden Triangle universities last week
 
John Rennie
John Rennie
@user8718165 so that's what the phrase An object at rest in F moves at a constant velocity in frame F’ means.
 
Emilio Pisanty
Emilio Pisanty
Imperial, UCL, King's, Oxford
 
John Rennie
John Rennie
@user8718165 In your frame $F$ the apple is at rest while in my frame $F'$ it (and you) are moving at $-v$.
 
user8718165
user8718165
@JohnRennie yes...got it...but if both you and I move at the same speed 10 m/s
 
Emilio Pisanty
Emilio Pisanty
4:09 PM
I mean, there's some lower-tier ones, I guess, but who has time to go to them?
LSE or QMUL or the like
:-P
 
John Rennie
John Rennie
@user8718165 if we are moving at the same velocity then we share the same rest frame
 
user8718165
user8718165
@JohnRennie Yes sir... but here both F frame and F' frame move with same velocity...so how is it $-v$? shouldn't it be 0?
 
Loong
Loong
@EmilioPisanty It's an old value: physics.nist.gov/cuu/pdf/codata86.pdf
 
Emilio Pisanty
Emilio Pisanty
@Loong 86!?
 
Loong
Loong
Chernobyl year
 
Emilio Pisanty
Emilio Pisanty
4:12 PM
@Loong well, yes
but also
well before the conventional units were established
 
John Rennie
John Rennie
@user8718165 no. $F$ and $F'$ are moving at a relative velocity of $v$. That's why positions in $F$ are related to positions in $F'$ by $r(t) = r'(t) + vt$.
 
user8718165
user8718165
@JohnRennie oh didn't see it...sorry...thank you so much!
 
Loong
Loong
@EmilioPisanty Some chemistry schoolbooks still have pre 1982 versions of STP, or even pre 1961 versions of amu.
 
Emilio Pisanty
Emilio Pisanty
@Loong That's barely within the uncertainty. The lower limit of 1.60217733(49) is 1.60217684
hmmmmm
it maybe bears looking more closely
those historical values do seem to jump around a fair bit
 
Loong
Loong
The last jump was because of the 2019 redefinition of the SI base units.
 
DanielSank
DanielSank
5:04 PM
Hi, everybody.
Que tal, Emilio?
 
 
1 hour later…
Jake Rose
Jake Rose
6:28 PM
@EmilioPisanty forgetting Cambridge in that list ;)
2
 
Wanting to be anAndroidDevelor
Wanting to be anAndroidDevelor
6:51 PM
Hello?
Im currently doing research on my career path as an assignment given by my university
Im currently doing physics
I have strong interest in physics
Ideas like "digital physics", "Aspect of theory of computation in physics" and "Church–Turing thesis and physics" all interest me
If possible, I want to do research in field that merge computability theory and physics
is there a name for this field or a close field that carry out research in these field?
 
Emilio Pisanty
Emilio Pisanty
7:21 PM
@JakeRose well caught
The joke, that is
@DanielSank pretty good =)
 
DanielSank
DanielSank
7:55 PM
Glad to hear it. @EmilioPisanty.
Good here too.
 
Novalium Company
Novalium Company
When we light up a fire, the atoms of the wood get heated up and start to turn into gas form. They interact with the oxygen in the air. Two questions. Why the interqction with oxygen and how the process of burning continues without further heat source?
@WantingtobeanAndroidDevelor I think you will enjoy Android Studio more. Sure you know Java.
 
Wanting to be anAndroidDevelor
Wanting to be anAndroidDevelor
?
 
Novalium Company
Novalium Company
@WantingtobeanAndroidDevelor your name.
 
Wanting to be anAndroidDevelor
Wanting to be anAndroidDevelor
ye
but I don't like developing android apps
 
Novalium Company
Novalium Company
I'm 17, so I can't give you any career advices :P
 
Novalium Company
Novalium Company
8:20 PM
2 questions about fire: How is fire self-sustained? The oxidizing agent (Oxygen) interqcts with the woods atoms (now in gas state) and the oxygen makes the wood atoms to loose electrons and therefor the wood collapses into CO2 and other smaller compounds?
A freshly cut apple's atoms will interact with the oxygen and the oxygen (being an oxidizing agent) will make the apple loose electrons (and the oxygen will gain them) and the apple starts to look a bit dead, correct?
 
Jake Rose
Jake Rose
8:58 PM
@NovaliumCompany most of what you said is iffy at best. Your best option is to read a chemistry textbook. Or google the science of burning etc
 
user280247
9:19 PM
@NovaliumCompany In chemical reactions, even when they are thermodynamically favorable, there is a 'hill' to go through, called energy barrier. It is somehow as water going through a mountain, 'trying to reach' a valley. This makes the reactions very slow, so slow that they practically do not occur.Once the reaction starts, by some external input of energy, the heat released by the products can be absorbed by the reactants.
 
user280247
Microscopically, I guess that the velocity increases and so the collisions now lead to the products
 
PM 2Ring
PM 2Ring
Activation energy
In chemistry and physics, activation energy is the energy which must be provided to a chemical or nuclear system with potential reactants to result in: a chemical reaction, nuclear reaction, or various other physical phenomena.The activation energy (Ea) of a reaction is measured in joules (J) and or kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol).Activation energy can be thought of as the magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state. For a chemical...
 
user280247
But this might be not the case, even exactly the opposite...or worse. (As far as I now I have never said something exact)
 
user280247
I'm reading susskind's book theoretical minimum, and found this expression:
 
user280247
$x^2 + y^2 = sin(x y)$
 
user280247
9:30 PM
If we can't easily transform it into a f(x,y); how to derivate it?
 
PM 2Ring
PM 2Ring
@santimirandarp Use implicit differentiation.
 
user280247
Is that function some kind of special thing?
 
vzn
vzn
9:48 PM
 
PM 2Ring
PM 2Ring
@santimirandarp Maybe, but I don't recognize it as having any special significance. But it is symmetrical in x & y. Maybe take a look at its graph.
 
vzn
vzn
↑ more breakthru experimental work favoring realism & directly refuting copenhagen interpretation
 
user280247
@PM2Ring I was wondering if x and y could be separated. Fine, thanksss
 
PM 2Ring
PM 2Ring
@santimirandarp I doubt they can be separated. Did you figure out how to differentiate it yet?
 
Ryan Unger
Ryan Unger
wolfram alpha won't plot it
 
user280247
9:52 PM
No,I'm trying to think about the function first. I dont know why $y$ should be a function of $x$
 
PM 2Ring
PM 2Ring
@RyanUnger Oh. That's a shame. But I don't blame it. ;)
 
Ryan Unger
Ryan Unger
It's not obvious to me that there are points satisfying that equation
except for (0,0)...
 
PM 2Ring
PM 2Ring
The LHS is like a circle. But if we do x = r cos(t), y = r sin(t), we get a horrible mess on the RHS.
 
Ryan Unger
Ryan Unger
according to Quora I'm right
the only solution is (0,0)
now $x^2-y^2=\sin(xy)$ is cool as hell
 
user280247
nice
 
PM 2Ring
PM 2Ring
10:00 PM
Actually, using that parameterization, $\sin^{-1}(r^2)/ r^2 = \sin 2\theta / 2$
 
user280247
Sorry for this question but if the function can be plotted it means that it is possible to find y=f(x), isnt it?
 
user280247
Or this is always the case?
 
Ryan Unger
Ryan Unger
you can do that locally by the implicit function theorem
but you need to learn how to implicitly differentiate first
 
user280247
I know how to do it but it doesn't imply I understand it, in fact I dont...
 
user280247
should read some book or video about that
 
Ryan Unger
Ryan Unger
10:06 PM
do you know what partial derivatives are
 
user280247
yes
 
user280247
but this kind of function $y^2 + y = x + x^2$ is something I haven't seen before, or haven't paid attention to.
 
Ryan Unger
Ryan Unger
@santimirandarp ok so the theorem is that you have a function $f:\Bbb R^2\to\Bbb R$ and look at the set $f^{-1}(0)$, say. Suppose next that $(x_0,y_0)\in f^{-1}(0)$ and also that $(\partial_xf,\partial_yf)(x_0,y_0)$ is not the zero vector
 
user280247
wtf
 
Ryan Unger
Ryan Unger
then there exists some $\varepsilon>0$ such that $B_\varepsilon(x_0,y_0)\cap f^{-1}(0)$ can be represented as the graph of a function $y(x)$
 
user280247
10:11 PM
wait. Is this a function $y^2 + y = x + x^2$?
 
Ryan Unger
Ryan Unger
in your case take $f(x,y)=y^2+y-x-x^2$
 
user280247
cause you cant have an expression y(x),at least at first sight
 
Ryan Unger
Ryan Unger
now compute the vector $(\partial_xf,\partial_yf)$
 
user280247
but f(x,y) = 0
 
Ryan Unger
Ryan Unger
no
It equals that when you choose $x,y$ to give that
like literally
but it's not zero for every $x$ and $y$
$f(x,y)$ is just a function here
$y^2+y=x+x^2$ is not a function, it's a locus of points
it's the set $\{x,y:f(x,y)=0\}$
 
Danu
Danu
10:21 PM
o/
oh hey, @RyanUnger, long time no see
You're interested in Riemannian geometry right?
suppp @ACuriousMind
 
ACuriousMind
ACuriousMind
@Danu \o
 
Danu
Danu
Here's a question
Given two two-forms, what's the simplest way of making a (0,4)-tensor which is an algebraic curvature tensor (i.e. anti-symm in the first and second index, in the 3rd and 4th index, and satisfying Bianchi)?
I have stumbled upon one way in my research
and I'm curious if it's in some sense the best/only/simplest way
The one I've found is the following: Given two two-forms $\alpha,\beta$, one can define the symmetrized tensor product $\alpha\vee\beta:=\frac{1}{2}(\alpha\otimes\beta+\beta\otimes\alpha)$
 
ACuriousMind
ACuriousMind
We've just had our weekly Skat game with considerable amounts of fermented hop tea, so my capacity for abstract thinking is...limited :P
 
Danu
Danu
One can also form the Kulkarni-Nomizu product $\alpha\otimes_{KN}\beta(A,B,C,D):=\alpha(A,C)\beta(B,D)-\alpha(A,D)\beta(B,C)+\alpha(B,D)\beta(A,C)-\alpha(B,C)\beta(A,D)$
One can define thies $\otimes_{KN}$ (normally denoted by \owedge, which chatjax doesn't know) for arbitrary (0,2)-tensors; it always maps into $\Lambda^2 T^*\otimes \Lambda^2T^*$. When they are both two-forms, it's an element of $S^2(\Lambda^2T^*)$ but it does not satisfy Bianchi
However, the combination $\alpha\otimes_{KN}\beta+4\alpha\vee\beta$ does define an algebraic curvature tensor
So my question is, vaguely, is there any simpler product of 2-forms that yields an algebraic curvature tensor?
Is this essentially the only one, or are there many others?
@ACuriousMind No worries :) How's life?
 
ACuriousMind
ACuriousMind
@Danu It's great :) Finally warm weather 'round here
 
Danu
Danu
10:31 PM
Yassss, same here in Hamburg
fucking great today
 
Ryan Unger
Ryan Unger
@Danu possibly
@Danu hi, how are you?
 
Danu
Danu
Good! How about you?
 
Ryan Unger
Ryan Unger
can't complain
 
Danu
Danu
Are you still in.... Kentucky, was it?
 
ACuriousMind
ACuriousMind
Though now there's a thunderstorm approaching, great atmosphere nevertheless
 
Ryan Unger
Ryan Unger
10:35 PM
It was Tennessee, and no
 
Danu
Danu
Ah, shit. Right
 
Ryan Unger
Ryan Unger
I'm at home now, going to Princeton in a couple days
 
Danu
Danu
Nice! Are you a student there?
 
Ryan Unger
Ryan Unger
Going there for a summer school, starting PhD there in the fall
 
Danu
Danu
Or are you going for the geometric analygis weeks
Yeah, nice
Congrats on getting into Princeton! :D
 
Ryan Unger
Ryan Unger
10:37 PM
Thanks
 
Danu
Danu
Best school in the world, I guess
 
Ryan Unger
Ryan Unger
I would have killed for Columbia...
It's decent :P
 
Danu
Danu
Really? Any specific profs yo uhave in mind? Or for other reasons?
 
Ryan Unger
Ryan Unger
My mathematical hero is at Columbia
 
Danu
Danu
who's that?
 
Ryan Unger
Ryan Unger
10:37 PM
Simon Brendle
 
Danu
Danu
Oh, okay :)
Ricci flow huh
 
Ryan Unger
Ryan Unger
@Danu upside down wedge?
 
Danu
Danu
@RyanUnger \vee is a (reasonably popular) notation for symmetrized tensor product
 
Ryan Unger
Ryan Unger
@Danu and mean curvature flow, minimal surfaces, general relativity
That's $\odot$ in Ricci flow world
 
Danu
Danu
Right, that's another option. I like the $\vee$ because it looks dual to $\wedge$ :)
 
Ryan Unger
Ryan Unger
10:40 PM
That's a good point
 
Danu
Danu
I happen to be taking a course on Ricci flow in my spare time atm :D
Never learned any serious analysis, but this actually isn't TOO bad so far
 
Ryan Unger
Ryan Unger
Ricci flow is actually not that bad. Post-Perelman is when things got crazy.
 
Danu
Danu
@RyanUnger Are you interested in min-max theory type stuff? I'd love to learn about that but have no idea where to start (I'm talking about this Neves-Marquez stuff)
 
Ryan Unger
Ryan Unger
There's a purely analytic proof of the Poincar\'e conjecture that gets heavy.
 
Danu
Danu
@RyanUnger Huh, interesting
 
Ryan Unger
Ryan Unger
10:41 PM
I'll probably end up doing min-max type things, yeah.
 
Danu
Danu
cool
some people in Munich told me this was a good area to get into now
 
Ryan Unger
Ryan Unger
I think it's a gamble if you're not close to the big guys in the field already
 
Danu
Danu
yea
but at least it's hot
 
Ryan Unger
Ryan Unger
Like it's probably hard to just pick a problem and go
 
Danu
Danu
that's already a big plus
 
Ryan Unger
Ryan Unger
10:42 PM
Marques gave me a massive reading list
 
Danu
Danu
You're going to be working with him?!
 
Ryan Unger
Ryan Unger
He agreed to advise me
Nothing is set in stone
 
Danu
Danu
aaaawesome :D
so you got nothing to worry about hehe
 
Ryan Unger
Ryan Unger
He has 10 students right now
 
Danu
Danu
you ARE close to the big guy
 
Ryan Unger
Ryan Unger
10:43 PM
Yeah
 
Danu
Danu
oh, shit, that's a lot. Well, big group/community is good too
shared seminars and such
 
ACuriousMind
ACuriousMind
May 23 at 21:38, by ACuriousMind
meanwhile, I'm sitting over here analyzing a language where data type type type. is a legal variable declaration...
 
Ryan Unger
Ryan Unger
It's 6 at Princeton and then 4 coadvised in south America
he's (his wife) having another baby next semester
so maybe I'll have to go with someone else
I don't think anyone is graduating next year
 
Danu
Danu
hmm
Either way, you're probably going to be in a really great position
Princeton is an amazing place to be a grad student
 
Ryan Unger
Ryan Unger
Yeah it should be fine
 
Danu
Danu
10:45 PM
any chance you're going to the summer school organized by the IAS in July**?
 
Ryan Unger
Ryan Unger
I didn't know there was one in August. What's it about?
 
Danu
Danu
It's near Salt Lake City
 
Ryan Unger
Ryan Unger
Oh PCMI
 
Danu
Danu
ya
I'm going there ^^ Hope it'll be fun
 
Ryan Unger
Ryan Unger
Can you send me a link? I don't know anything about it.
 
Danu
Danu
10:46 PM
the topics are kind of wide apart
My research is somewhat close to some of them
 
Ryan Unger
Ryan Unger
Yeah that's not really up my alley
What are you working on?
 
Danu
Danu
constructions of quaternionic Kähler manifolds
 
Ryan Unger
Ryan Unger
@ACuriousMind what?
 
Danu
Danu
it's a bit related to Higgs bundles/Hitchin moduli space stuff
 
Ryan Unger
Ryan Unger
You know I finally found out what a twisted connected sum is
 
Danu
Danu
10:48 PM
(some of the lectures are about that)
 
Ryan Unger
Ryan Unger
Only took going to three talks by Donaldson
"APPLICATION DEADLINE: JANUARY 15, 2019" lol
Is there some online list of summer schools and conferences
 
Danu
Danu
yeah, many partial lists
it's kind of a shit show but if you work on it a bit you can catch most things
there's the geometry mailing list, which is already pretty good
It's operated by your old university(?) listserv.utk.edu/archives/geometry.html
 
Ryan Unger
Ryan Unger
Oh yeah
I have no idea who maintains that
 
Danu
Danu
I have a list of like 20-30 bookmarks for this stuff
 
Ryan Unger
Ryan Unger
I'm guessing Fernando Schwartz started it
 
Danu
Danu
10:51 PM
If you want I can give you some sometime. I've gotta go now though! Good night!
 
Ryan Unger
Ryan Unger
Sure!
Ciao
 
ACuriousMind
ACuriousMind
@RyanUnger Ah, don't mind me. It's just a bit surreal that things I might have cared about two years ago now seem a lifetime in the past
 
Ryan Unger
Ryan Unger
@ACuriousMind you can always come back into the fold
 
user280247
@RyanUnger How can I know when something is or is not a function? like y^2+y=x^2+x
 
user280247
I've partially understood what you say, I guess
 
Ryan Unger
Ryan Unger
10:59 PM
Do you know what functions are?
 
ACuriousMind
ACuriousMind
@RyanUnger Ah, I don't really want to. I would've been a mediocre researcher at best, but I feel pretty good about what I do now
But just two years ago the thought of not doing physics for a living would've seemed alien, Now it's...normal
 
user280247
@RyanUnger uhmm well to me they are colums of data which can be plotted and if they obey a simple rule they are usually functions, plus some extra
 
user280247
like continuity
 
user280247
gonna sleep anyway. gb
 
Ryan Unger
Ryan Unger
@santimirandarp ok that's very wrong
I see what the issue is
@ACuriousMind is there a canonical PSE answer for this
 
ACuriousMind
ACuriousMind
11:08 PM
It seems more like a math question, actually. I think most physicists understand the notion of a function as a map between spaces, even if their functions usually are only between various incarnations of $\mathbb{R}^n$.
 
Ryan Unger
Ryan Unger
@ACuriousMind I hope they don't make me teach calculus because I didn't expect to go from implicit differentiation to "what is a function"
 
ACuriousMind
ACuriousMind
Oct 14 '16 at 20:44, by ACuriousMind
I don't even know what calculus is
 
Ryan Unger
Ryan Unger
3 years ago!
 
ACuriousMind
ACuriousMind
Yes, since then I've learned that "calculus" seems to be a vague term for "doing analysis without knowing what analysis is" :P
 
Ryan Unger
Ryan Unger
@ACuriousMind yeah just learn the rules like product rule, various integration tricks, and convergence tests for series
and then there's some canonical problems you need to know how to solve
like filling a conical tank and computing how fast the water level is rising
that's basically calc 1 and 2
 
PM 2Ring
PM 2Ring
11:28 PM
@RyanUnger If it's any consolation, his questions here are better than what he asks us in the Python room.
 
Ryan Unger
Ryan Unger
to be fair, asking why one can write $y=y(x)$ is a very good question
But then I think he showed that he doesn't know why it's a good question...?
 
user280247
@PM2Ring would it be too difficult for you to be less aggressive?
 
PM 2Ring
PM 2Ring
@RyanUnger True. It's confusing because $y$ is doing 2 different jobs. OTOH, you should get exposed to notation like that in high school.
 
user280247
even doing stupid questions i'm rather similar to any human being
 
PM 2Ring
PM 2Ring
@santimirandarp Sorry, I didn't mean to be aggressive. And I'm definitely not suggesting that you're stupid. But in my experience, your questions do tend to be a bit disorganised.
 
user280247
11:34 PM
well yes, and you're right
 
PM 2Ring
PM 2Ring
If I thought you were stupid I wouldn't waste my time trying to teach you stuff.
 
Ryan Unger
Ryan Unger
@santimirandarp so look up what I function is
I'm sure there's a million articles aimed at high school students
my explanation is probably not what you're looking for
 
user280247
i won't ask again in any of those sites
 
user280247
i will possibly. bye
 
Ryan Unger
Ryan Unger
?
 
PM 2Ring
PM 2Ring
11:44 PM
Here's a fun little calculus problem. Find the cone of minimum volume that contains a unit sphere. Bonus points for determining if it's also the cone of minimum (curved) surface area.
 

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