/sqt/ /qtddtot/ - stupid questions thread

[Anonymous No.15599798]

Formerly: >>15566555

>what is /sqt/ for?
Questions regarding maths and science. Also homework.
>where do I go for advice?
>>>/sci/scg or >>>/adv/
>where do I go for other questions and requests?
>>>/wsr/ >>>/g/sqt >>>/diy/sqt etc.
>how do I post math symbols (Latex)?
rentry.org/sci-latex-v1
>a plain google search didn't return anything, is there anything else I should try before asking the question here?
scholar.google.com
>where can I search for proofs?
proofwiki.org
>where can I look up if the question has already been asked here?
warosu.org/sci
eientei.xyz/sci
>how do I optimize an image losslessly?
trimage.org
pnggauntlet.com
>how do I find the source of an image?
images.google.com
tineye.com
saucenao.com
iqdb.org

>where can I get:
>books?
libgen.rs
annas-archive.org
stitz-zeager.com
openstax.org
activecalculus.org
>articles?
sci-hub.st
>book recs?
sites.google.com/site/scienceandmathguide
4chan-science.fandom.com/wiki//sci/_Wiki
math.ucr.edu/home/baez/physics/Administrivia/booklist.html
>online courses and lectures?
khanacademy.org
>charts?
imgur.com/a/pHfMGwE
imgur.com/a/ZZDVNk1
>tables, properties and material selection?
www.engineeringtoolbox.com
www.matweb.com
www.chemspider.com

Tips for asking questions here:
>attach an image (animal images are ideal, you can grab them from >>>/an/. Alternatively use anime from safebooru.donmai.us)
>avoid replying to yourself
>ask anonymously
>recheck the Latex before posting
>ignore shitpost replies
>avoid getting into arguments
>do not tell us where is it you came from
>do not mention how [other place] didn't answer your question so you're reposting it here
>if you need to ask for clarification fifteen times in a row, try to make the sequence easy to read through
>I'm not reading your handwriting
>I'm not flipping that sideways picture
>I'm not google translating your spanish
>don't ask to ask
>don't ask for a hint if you want a solution
>xyproblem.info

[Anonymous No.15600556]

Is there any place I can get Cantor’s Paradise articles for free?

[Anonymous No.15600625]

if you have something in a stable orbit around earth and you fire thrusters on it to push it further away from earth, does it:
speed up
slow down
eventually fall back into its stable orbit?

i'm asking because of this quote on imdb about the movie life (2017) and i dont understand:
>At one point the space stations orbit is degrading and the thrusters are fired to put it back into a stable orbit. To accomplish this the thrusters seem to fire down or towards the earth, this is incorrect, to gain altitude they would need to orbit faster so the thrust would be from the back accelerating them into a higher more stable orbit.

[Anonymous No.15600813]

>>15600625
to raise orbit you need to increase your orbital velocity, which is why you need to fire thrusters along the direction of the object's motion
this is how satellites reach geostationary orbit, they use a first maneuver to increase their orbit's aphelion to the geostationary altitude then once they reach the aphelion they do another maneuver to bring the perihelion to geostationary altitude as well
applying thrust away from earth would do jack shit, as you have Earth's gravity countering that force and the only thing it would accomplish is reduce your orbital velocity

[Anonymous No.15600819]

>>15600813
why are you using aphelion/perihelion to describe something orbiting earth

the words are apogee/perigee

are you GPT2

[Anonymous No.15600823]

>>15600819
because I got my words mixed up lol

[Anonymous No.15600828]

>>15600823
too bad, heinlein sentences you to 15 years asteroid mining

[Anonymous No.15600832]

Suicide suicide suicide

[Anonymous No.15601014]

>>15600832
nO thanks

[IM GLED I CAN SPA- No.15601063]

What science is used to physically render image correctly, like how refraction and reflections happen between multiple translucent objects,
in the most basic way, how is the line, shape and color, values placed, so that the object can be maximally realistic.according to the physicallity of the object or image?

pls draw over on any of the picture to illustrate your points, using one as reference or vice versa

[IM GLED I CAN SPA- No.15601068]

>>15600832
just aBIT

[Anonymous No.15601109]

>>15601063
Light refraction and reflection are well understood phenomena that can be mathematically formalized, it's called optics. A computer can thus simulate single beams of light and calculate how they would bounce around objects, the old ray tracing. This is a simplification, as it's too complicated to simulate actual photons, but it works.

[IM GLED I CAN SPA- No.15601121]

>>15601109
u mean use blender? wasnt there some way it is done before computer? or just how it is drafted, i undertand there are shading tutorial so this one could be the same?

[Anonymous No.15601202]

>>15601121
Art imitates the effect of light, simulating light itself required computers because it is very computationally intensive. Full ray-tracing even more so.

[Anonymous No.15601218]

>>15601202
how about ala perspective drawings, lines and dots. calculated drawing like it was done with books.

i guess i just wanna, get a "feel" of the traditional, which, also seems to be precise and also correct

[Anonymous No.15601246]

>>15601218
>i guess i just wanna, get a "feel" of the traditional
then take an art class

[Anonymous No.15601251]

>>15601218
Something tells me you're retarded

[Anonymous No.15601266]

>>15601218
that's less about optics and more about the elements of drawing. traditional art isn't about making things "correct" per se, but making them look believable.
>>15601246
>>15601251
i agree with both sentiments

[...guess im done (almost) No.15601297]

>>15601246
Dont know which one deals with this specific.

I have understood the rest. This one left.
>>15601251
Whoa. You are a genius. Do it in a diagram then. Or part of your brain just relies on blender?
>>15601266
Well physically corect IS the believability. Cant science just the How? This is not rocket science
>sentiments
Well make a convincing diagram then.

[Anonymous No.15601316]

>>15601297
> Dont know which one deals with this specific.
> ala perspective drawings
You already answered your own question.

[Anonymous No.15601352]

What kind of math is needed to understand quantum mechanics?

[Anonymous No.15601360]

>>15601352
Linear algebra and some calculus.

[Anonymous No.15601378]

>>15601360
Fugg, linear algebra might be beyond me.

[...guess im done (almost) No.15601477]

>>15601316
...perspective drawings dont include refractions. I figured reflections on my own. And that took awhile. I thought a book could help make this easier.

Do you know anything perhaps.

[Anonymous No.15601491]

>>15601477
Bro just read a book optics it's not hard

On the other hand, you're operating in 2d space and Illusion is much more desirable than realism in art anyway, why would you wanna learn all that shit

[Anonymous No.15601513]

>>15601491
Wellbro can i get some pointers. I havent been a decorated noble prize winners in physics, no matter how "physically correct renders" turns me on.

Maybe i ll go to g now
>illussion
Confusing. There are no better illussion that realism these days. I d bite your clues but i really dont know what you mean by illussion.

You d be suggesting "freestyling" the renders since theres only one way to scientifically 'visualize' physics of rendering anyway.

[Anonymous No.15601555]

>>15601513
Well, people don't really care about realism as long as your artwork seems plausible to the First glance. They care about being visually stunned, either with beauty or with terror. At least, thats my two cents about it

[It s not the right illussion anyway/reveresed No.15601567]

>>15601555
Well nevermind the clout...or the cringe. I m just looking physically correct rendering. Which supposedly is /sci/?

[Anonymous No.15601657]

Let [math](X,d)[/math] be a separable metric space. A Borel regular measure [math]\mu[/math] on [math]X[/math] is said to be uniformly distributed if every ball in [math]X[/math] has finite, positive measure which is independent of its center point, i.e. there exists a map [math]C_\mu: \mathbb{R}_{>0} \to \mathbb{R}_{>0}[/math] such that [math]\mu(B(x,r)) = C_\mu (r)[/math] for all points [math]x \in X[/math] and radii [math]r > 0[/math].

I want to prove that if [math]\mu, \nu[/math] are as above then they are scalar multiples of each other. Clearly, these measures must be [math]\sigma[/math]-finite, so one can apply tools like RN derivatives, Fubini, etc.

My rough idea is to show that [math]\nu \ll \mu[/math] (this should follow from regularity somehow), deduce that [math]\frac{d\nu}{d\mu}[/math] exists, and then show (god knows how) it's constant almost surely, the constant being [math]\frac{C_\nu (1)}{C_\mu (1)}[/math]. However, I got stuck on the very first step of this plan. Does anyone have an idea?

[Anonymous No.15602047]

>>15599798
Guys I might be a retard but...
my EM book explains why charges macroscopically flow through a conductor with a constant speed by using Drude's model.
Of course the model is just a nice little story which is whoefully outdated.
Which later models give more accurate reasons for this phenomenon? Is there a path of increasing complexity? Do I have to read a trillion books about EM or is there a resource that condenses the various explanations in one single place???

[Anonymous No.15602149]

>>15602047
> Which later models give more accurate reasons for this phenomenon?
Turn back now while you still can young padawan. That is the deep, deep well of solid-state physics that you are asking to dive into.

> Is there a path of increasing complexity?
Yes, like much of physics it is an ever increasing case of "what you learnt already is not the full story or simply wrong". You may start with Drude's model and then the free electron model but it certainly doesn't stop there. Modern condensed matter physics widely uses quantum field theory.

> is there a resource that condenses the various explanations in one single place???
If there is I'm not aware of it. The field is vast.

[Anonymous No.15602268]

>>15602149
well, but what is the gist of why electrons macroscopically move at a constant speed through a conductor?

[Anonymous No.15602390]

>>15600813
forgive my improper terms, but if you are orbiting earth "anticlockwise" and you fire your thrusters straight "up" away from earth, why does this reduce the speed you are travelling "anticlockwise" (orbital velocity)?

[Anonymous No.15602400]

>>15602268
> why electrons macroscopically move at a constant speed through a conductor
they don't, drift velocity is the statistical average of all the their speeds.

[Anonymous No.15602532]

>>15601297
>Well physically corect IS the believability
no, it's not. They can overlap, sure, but sometimes the truth is stretched to make certain parts stand out or vice versa.
"Physically correct rendering" is simply intuition gained from experience OR drawing from life or a photo and duplicating that. Otherwise no math is actually involved with it if you're working on a "3D object" on a 2D canvas since you can't have any actual parameters of light in 3D space (other than ratio and perspective) since the 3D object simply does not 'exist' on this plane or medium

[Anonymous No.15603048]

>>15602400
>drift velocity is the statistical average of all the their speeds
statistical average = macroscopic phenomenon

[Anonymous No.15603224]

>>15599798
What would the equation for a wave like this be?
Standing waves are hard enough without the little waves superimposed on them

[Anonymous No.15603810]

>>15603224
the product of two cosines, where one has a frequency significantly higher than the other

[Here i listen No.15604330]

>>15602532
Well you are correct probably. But i guess i work abit differently and i rely on the howto draw shadow theory, still, even after all this time to assure myself of correctness... also 3dcg rendering is written with math...

I guess i need some prop up? A correct one. Fine if there isnt, but scoro wrote so too, and the likes of galileo or whoever... so it shouldnt be weird.

[Anonymous No.15604655]

Help me suicide

[....so its beck, not solanin? Hello, beck No.15604775]

>>15604655

[Anonymous No.15606094]

>>15600625
firing thrusters away from the earth rotates your perigee/apogee forward no? at least that's what I remember from Kerbal Space Program

[Anonymous No.15607048]

Why does the partial derivative of a multivariate Taylor polynomial of order two with respect to x, equal to the partial derivative of the function with respect to x?

[Anonymous No.15607442]

Should I increase the size of my brain or is it unhealthy? (Assuming I can.)

[Anonymous No.15607456]

I'm reading a paper and I've come across this part I don't understand.

[eqn]
\dot{f}(\theta) = A(\theta) + f(\theta)B(\theta)
[/eqn]

There's an equation of the above form and the author says he's taking an integral to find the value of f which gives him an equation of the below form

[eqn]
f(\theta) = \int_\theta^\infty \exp\left[\int_\theta^x B(y) dy\right]A(x)dx
[/eqn]

Any idea what steps he could've taken here? I understand he's somehow getting rid of the f on the right-hand side in the first equation but I can't seem to get to the answer. He's not explaining what he's doing so this has to be something trivial I don't see.

[Anonymous No.15607707]

>>15604775
I would say kys, but...

[Anonymous No.15607815]

How exactly does creating an implosion ignite this metal core which then further causes a nuclear explosion?

[Anonymous No.15607860]

>>15607815
in short:
the nuclear explosion is the result of runaway fission, where one atom breaks down and the "fragments", upon hitting other atoms, cause them to break down in the same way, releasing a shitton of energy in the process
by imploding the core, you're forcing all of those atoms together, making it more likely that their decay products will hit each other

[Anonymous No.15607914]

>>15607860
How the hell can you prove that an nuclear explosion can occur using with math? Conceptually it makes sense. (I have taken math up till diff eq so don't be afraid to go deeper)

[Anonymous No.15608057]

if a soundwave is 1hz, does it go (up AND down) every second or does it go up one second, down the next?

[Anonymous No.15608063]

>>15608057
1 Hz is 1 complete oscillation every second, so your first example is 1 Hz and your second is 2 Hz

[Anonymous No.15608068]

>>15608057
There is more than one type of soundwave, and they do not have to be sinusoidal to be periodic so either can be correct.

[Anonymous No.15608073]

>>15608063
ty anon

[Anonymous No.15608867]

>>15607456
That is a first order differential equation and it looks they have solved it using Integrating Factors. It's a standard method you can google to explain.

[Anonymous No.15609455]

>>15608057
1hz
2hz

[Anonymous No.15610072]

what's the difference between a direction field and a slope field?

[Anonymous No.15610424]

Leisen.

[Anonymous No.15610549]

>>15608057
if a wave has a frequency of 1Hz, then it completes a full cycle in 1 second. your top drawing has a frequency of 1Hz.
>>15609455
red hz
blue hz

[Anonymous No.15610552]

>>15608057
(btw, your second drawing is neither 1Hz nor 2Hz)

[Anonymous No.15610559]

should i take a class for PLC programming is that still used in the industry nowadays? it seems pretty boring and oldschool

[Anonymous No.15610628]

>>15610549
>your top drawing has a frequency of 1Hz.
It doesn't since it's a triangle wave and it doesn't have a pure frequency (unlike a sine) but it is instead composed of multiple frequencies (see pic rel)
>>15603224
This >>15603810 but there is also a trig identity where it can be written as the sum of two sines/cosines (I don't remember) and this might help you analyse the thing as the sum of two solutions

[Anonymous No.15611707]

bump

[Anonymous No.15612319]

is there a name for fract(pi) aka ( pi - 3 )

[Anonymous No.15612352]

>>15612319
no, there is nothing useful about that value.

[Anonymous No.15614305]

bump

[Anonymous No.15614470]

>>15611707
>>15614305
stop bumping the thread, it's a waste of time and posts. the thread is slow, deal with it.

[Anonymous No.15614492]

bump

[Anonymous No.15614563]

>>15610628
>It doesn't since it's a triangle wave and it doesn't have a pure frequency (unlike a sine) but it is instead composed of multiple frequencies (see pic rel)
this is so pedantic its verging on being just wrong.

[Anonymous No.15614896]

>>15610628
"Frequency" doesn't imply a sine wave. The waveform is periodic, so has a period. The frequency is just the reciprocal of the period.

[Anonymous No.15614898]

>>15614563
It's just wrong.

[Anonymous No.15614913]

what did you guys think of the oppenheimer movie?

[Anonymous No.15614978]

>>15599798
How is an isobaric ODE a generalisation of a homogeneous ODE? Why is it that y=vx^m must make it separable?

[Anonymous No.15614980]

>>15614978
I don't see how this (homogeneous ODE) is connected to isobaric ODEs. A homogeneous function f(x,y) has the sum of the powers in each term equal.

[Anonymous No.15614981]

>>15614978
>>15614980
See >>15614314

[Anonymous No.15615064]

What's a good book for learning undergraduate chemistry?

[Anonymous No.15615097]

>>15615064
Chemical principals third edition
richard e dickerson harry b gray

It is an older book(1978) but newer texts don't do the best job at explaining concepts.

[Anonymous No.15615131]

if electricity returns through the earth why can't I steal power with a metal rod in the ground?

[Anonymous No.15615142]

Odd site, I present it unchallenged
https://criticalcheck.wordpress.com/2021/12/15/dna-discovery-extraction-and-structure-a-critical-review/

[Anonymous No.15615233]

>>15601297
>This is not rocket science
No, rocket science is relatively simple. Translating the physics of light to paper via a hand drawing in a way that is scientifically accurate is extremely complicated.

[Anonymous No.15615986]

Does anyone have the full resolution of this?

[Anonymous No.15616339]

I have an undergraduate physics degree and want to read Lang's Algebra cover to cover. I have skimmed the first few pages and it seems relatively straightforward and understandable, but is there anything later on that I would be missing that I need to learn beforehand? Would it be worth going through an undergraduate book first?

[Anonymous No.15616351]

>>15616339
no

[Anonymous No.15616402]

>>15615131
Electrical power isn't simply the presence of electrons, it's the flow of electric charge originating from a potential energy difference (voltage). Sticking a metal rod in the ground and expecting electrical power to flow is analogous to putting a waterwheel in a stationary lake and expecting it to turn. There's water in the lake, sure, but it's in a low-energy state. If you want the waterwheel to turn, you need water with a higher amount of (gravitational) potential energy to flow down the wheel. Similarly, if you want electricity, you need charges with a higher amount of (electrical) potential energy to flow through the rod to lower energy state, e.g. the ground.

[Anonymous No.15616420]

>>15615131
you sort of can, look up dollard

[Anonymous No.15616615]

Are superconductors the key to "levitation" technology? Will we be able to make something that counter acts the Earth's magnetic field making us float?

[Anonymous No.15616630]

>>15616615
Levitation with supporting infrastructure, yes. Sci-fi-esque levitation no.

[Anonymous No.15616729]

Anyone know the average age of COVID death?
thanks in advance

[Anonymous No.15617247]

>>15614913
pretty decent, super corny scenes sometimes. Shows how bad the Red Scare actually was, which was cool. Nolan doesn't know when to not play music though, that was annoying

[Anonymous No.15617397]

Look out there's a suicide coming

https://youtu.be/9HeEFxgktVg

[Anonymous No.15617531]

what do people mean when talking about entropy in a more statistical sense? not sure if phrasing right, but am familiar with intro undergrad thermodynamics course but know its also used in less heat-transfer related contexts.
more specifically, would it be possible to actually calculate some metric of entropy to describe these cellular automata am working with?
given pic related could you calculate which has higher entropy?

[Anonymous No.15617580]

In regards to consciousness, why do they say you can only ever know that you are conscious, you can't prove if anyone else is?

I get the idea that a machine could emulate a conscious being perfectly and so there is no way to verify, but that seems to come at it only from a backbox perspective. doesn't it stand to reason that consciousness must have hardware somewhere in the brain and if you are conscious than the hardware would look differently then if you just had a million node matrix in the same spot?

[Anonymous No.15617608]

>>15617580
this is getting far more philosophy than science at this point, but one could note that there's not really a way to prove the brain is responsible for consciousness as opposed to some external force. Sure, that's the obvious conclusion... but technically speaking, the only way to actually prove it would be to affect your own consciousness through your own brain, otherwise known as "giving yourself brain damage".
Assuming that the brain itself is responsible for consciousness is, in some sense, assuming that everyone is conscious to begin with

[Anonymous No.15617624]

>>15617608
but even if the brain is not responsible for conciseness it again must have some hardware to interact with this external force, "IO" if you will. someone who's not conscious would lack this hardware / it wouldn't be connected to anything / they'd need a brain only substitute to emulate the portion they'd normally get from the external factor. there would have to be some physical evidence. Maybe we can't detect what it is with modern technology, but if it interacts then it must be tangible on some level which means we can measure it or its effects and it means we can also not when it doesn't effect anything

right?

[Anonymous No.15617681]

Which class of lever is this machine?
2nd class or 3rd class?

[Anonymous No.15617950]

Someone explain to me in a easy way semantics and models of predicate logic

[Anonymous No.15618306]

>>15614896
>The frequency is just the reciprocal of the period.
Frequency of what? How many times it repeats? This isn't frequency
If that were so then explain why buildings can collapse if you hit them with a triangle wave of different "frequency" than the resonant frequency
>>15614563
>>15614898
It's not wrong. A triangle wave has multiple frequencies. Explain why triangle, square and sine waves of the same frequency sound different and why the square is the loudest then
https://onlinetonegenerator.com/

[Anonymous No.15618504]

>>15618306
because they have different waveforms?
you would think that the obvious clue would be in the fact that you're trying to appeal to how loud the wave sounds when that's unrelated to the frequency

[Anonymous No.15618617]

>>15618306
It really is amazing how basically nobody on /sci/ of all places seems to have ever computed a Fourier transform.

[Anonymous No.15618646]

Hi, may someone please help me out with this question?

[Anonymous No.15618650]

>>15618646
Here's the MS. I get the first line, but don't understand why in line 2 you have to multiply dv/ds by v

[Anonymous No.15618651]

>>15618646
consider that acceleration is the antiderivative of velocity

[Anonymous No.15618748]

>>15618650
[math]\dfrac{dv}{ds}[/math] is the change in velocity with respect to position. However acceleration is the change in velocity with respect to *time*. So by the chain rule:
[eqn]a = \frac{dv}{dt} = \frac{ds}{dt} \frac{dv}{ds} = v \frac{dv}{ds}[/eqn]

[Anonymous No.15618764]

>>15618748
You are so handsome.
Cool, thank you.

[Anonymous No.15618765]

>>15618650
[eqn]
a = \frac{dv}{dt} = \frac{ds}{dt} \frac{dv}{ds} = v \frac{dv}{ds}
[/eqn]
This is just the chain rule.

[Anonymous No.15618789]

>>15618650
I'm having problems with part b), I'd really appreciate some help.

[Anonymous No.15618794]

>>15618789
I don't understand why in line 2 they divided by $1+(tan\frac{\pi}{4})(tan(arctan\frac{1}{2}))

[Anonymous No.15618800]

>>15618794
$1+(tan\frac{\pi}{4})(tan(arctan\frac{1}{2}))$

[Anonymous No.15618812]

>>15618794
It's a standard trig identity: https://en.wikipedia.org/wiki/List_of_trigonometric_identities#Angle_sum_and_difference_identities

The identity for [math]\tan(\alpha - \beta)[/math]

[Anonymous No.15618840]

I want to work with AI in the future bros. Am I better of doing a BSc in Compsci + Math (230ECs), or in AI (180Ecs)? Either way I am doing a MSc in AI afterwards. I am leaning towards the latter, and am hoping some experienced anons can admonish/affirm that feeling.

[Anonymous No.15618856]

>>15617531
Entropy is defined for a macrostate consisting of all the microstates that share an observable property like temperature. Basically for every temperature the system can take a certain number of configurations, at high temperature there are many, at low temperature the system is frozen into one or a few low-energy configurations. The available configurations for a given temperature are described by a probability distribution. If the i-th microstate has probability [math]p_i[/math] then the entropy of the macrostate is [math]S = -k_B \sum_i p_i \log p_i [/math]. Even if you have no notion of temperature you can still define the entropy of any discrete probability distribution in this way, like what people do in information theory.
However I find that for entropy of CAs there is literature using some weird topological concepts like https://content.wolfram.com/uploads/sites/13/2018/02/12-2-1.pdf that I don't really understand but maybe you know more about topology

[Anonymous No.15618870]

>>15618812
>https://en.wikipedia.org/wiki/List_of_trigonometric_identities#Angle_sum_and_difference_identities
very cool, thank you!

[Anonymous No.15618874]

>>15617624
If you ever find something that's clearly a brain modem, ansible, whatever, to another plane of existence, then you've disproven that rule, I guess. Well, of course, there is the issue of knowing whether they're linked up to the same type of thing on the other side that you are.

[Anonymous No.15619189]

>>>/v/646081541

[Anonymous No.15619270]

I gotta study for europoorean country math exams for next year, what in the FUCK do I study? I feel overwhelmed looking at Khanacademy, do I look by grade or by subjects? I saw that it has a SAT study guide but I assume the SAT is less demanding cuz burgers lol + paid

for reference, I struggle with even basic operations like multiplaying fractions.
im a total retard around geometry. I somewhat understand statistics and linear/quadratic/cubic functions, but linear algebra and equations always confused me

so what pill you recommend to me bros? can I make it with ~2h of study time each day?
>inb4 underage
nigga i flunked out of HS to fuck bitches and grind

[Anonymous No.15619275]

>>15619270
You study math at Khan Academy. If you can't even work that out then I don't see much hope for you t.b.h

[Anonymous No.15619281]

>>15619275
i get that part, i just don't know what to study since its a site geared for americans, or if i should study by grade/topic

[Anonymous No.15619286]

>>15619281
Cover everything you don't know.

[Anonymous No.15619428]

is it possible to learn just gas kinetics or do I need to learn fluid dynamics in general
would be for just a hobby project

[Anonymous No.15619487]

>>15619428
only you can answer that since only you know what the project is

[Anonymous No.15619535]

>>15619487
you misinterpreted my question
I'm asking whether it's possible to learn the specific field of gas kinetics without learning anything else related to it

[Anonymous No.15619716]

How come climate scientists make the BOLDEST predictions when they have a literal sample size of 1 (one planet earth)?
Economists have much better data and better tested models in comparison and you'd laugh Krugman out of the room if he claimed that the world would collapse within 5 years if it didn't implement some policy.

[Anonymous No.15619805]

Consider a infinitely dimensional vectorspace V and a one-dimensional subvectorspace U. Let {b} be a basis of U. My question is, if there exists a a basis of V containing b, such that all basis vectors - with the exception of b itself - are orthogonal to b. Mind that the basis itself doesn’t have to be an orthogonal basis.

Can someone confirm that this wrong?

[Anonymous No.15619951]

>>15619716
What an absurd and idiotic statement. They have sample data going back millions of years from multiple sources about *this* planet. Just like economists have historical data to based their models upon for *this* planet's economy. You can argue about the conclusions those models come to but to say they are flawed because the sample size is 1 is fatuous and frankly wrong.

[Anonymous No.15619988]

>>15619951
>How dare you ask a stupid question! Now I am become mad. Seether of /sqt/s.

[Anonymous No.15620020]

extremely brainlet question prepare yourself.
i have this law that describes motion: x = 3(t^2), then average velocity is v = 6t,
but why, (x(t + n) - x(t))/n does not equal v(t)?

[Anonymous No.15620023]

>>15619988
It was a /pol/-tier post. If you claim otherwise then just how young are you?

[Anonymous No.15620024]

>>15618306
>Explain why triangle, square and sine waves of the same frequency
>same frequency
hmmm. also they have different tones but have the same pitch.
>inb4 overtones
sine waves have overtones too.
>If that were so then explain why buildings can collapse if you hit them with a triangle wave of different "frequency" than the resonant frequency
that works with sine waves too.
>>15618617
>It really is amazing how basically nobody on /sci/ of all places seems to have ever computed a Fourier transform.
a fourier series is when you write a continuous, hopefully periodic function in terms of a linear combination of functions that look like [math]\sin(2 \pi x)[/math], [math]\sin(4 \pi x)[/math], [math]\sin(6 \pi x)[/math], etc. a fourier transform is when you expand that to a continuous spectrum of frequencies. the family of functions that look like [math]\sin(2 \pi nx)[/math] is known as a basis. you know what other family of functions can be used as a basis? triangle waves!
https://ieeexplore.ieee.org/document/1437933

[Anonymous No.15620041]

>>15620020
x(t+n)=3(t+n)^2=3(t^2+2tn+n^2)=3t^2+6tn+3n^2
then the numerator is 3t^2+6tn+3n^2-3t^2=6tn+3n^2
divide through by n and you get 6t+3n
as n tends to 0 you end up with 6t as expected
where's the problem?

[Anonymous No.15620079]

>>15620041
i'm using a book a that introduces to differentiation without the limits definition,
i'm confused as why the numbers are not the same?
for example t1 = 19 and t2 = 20. distance covered = x(20) - x(19) = 117m in 1 second, so average speed of 117 m/s. but v(19) is 114 m/s and i expected x(20) to be x(19) + v(19).

[Anonymous No.15620094]

>>15619951
>They have sample data going back millions of years from multiple sources about *this* planet.
Yes, one planet.
>Just like economists have historical data to based their models upon for *this* planet's economy.
No, economists have data about multiple different economies. Coeteris paribus analysis is entirely reliant on that.
> You can argue about the conclusions those models come to but to say they are flawed because the sample size is 1 is fatuous and frankly wrong.
How is it not? Literally no other science would take anything with a sample size of 1 seriously.

[Anonymous No.15620112]

>>15620079
> i expected x(20) to be x(19) + v(19).
then you would be wrong because v(t) is not the average velocity, it is the instantaneous velocity at time t.

time doesn't suddenly jump from t=19 to t=20, it's a smooth function between those two points which is why calculus was invented in the first place.

[Anonymous No.15620130]

>>15620112
what does v(19) mean then?

[Anonymous No.15620147]

>>15620130
The velocity at time = 19 but that is different to the velocity at t = 19.1, 19.2, 19.31,19.35, etc etc.

[Anonymous No.15620170]

>>15620147
with R i found the mean of all the instantaneous velocities between [19, 20] in steps of 0.01 to be 117 so it all makes sense.
alright so the problem is that 1 second is too big of a time difference? because i discovered that for any function x(t) = n(t^2), v(t) = nt the difference was always missing by n (in this case 117 - 114 = 3).

[Anonymous No.15620222]

>>15620170
> alright so the problem is that 1 second is too big of a time difference?
what problem? I'm still not clear what you think the issue is.

[Anonymous No.15620250]

>>15620094
> Literally no other science would take anything with a sample size of 1 seriously.
There is only 1 universe, so how can we take the Standard Model seriously?

[Anonymous No.15620258]

>>15620250
because we dont care to model the universe but only see its side effects

[Anonymous No.15620262]

>>15620222
probably i don't understand the use of the derivative in this setting. what am i supposed to do with the velocity at a point of time if it can only approximately tell me where it is going to be next? i feel so filtered

[Anonymous No.15620302]

>>15620262
> what am i supposed to do with the velocity at a point of time
nothing until you get to integration, then you can use to calculate the change in position over time.

[Anonymous No.15620333]

>>15620302
ooooh wait so basically what i did here >>15620170? this is like the riemann sum but with dx being (20-19)/0.01
although it may not seem like it i already passed my calculus 1 course i'm just revisiting everything because i feel like i did not truly understood what calculus is all about.

[Anonymous No.15620334]

>>15620333
> this is like the riemann sum
correct

[Anonymous No.15620369]

Consider the products [math]X\times Y[/math] of two sets. If two elements [math]a,b\in X\times Y[/math] have the same image under both projections then they are the same. I want a nice way to prove this.
Here's what I have, consider a and b as maps [math]\{1\}\rightarrow X\times Y[/math], then if their composites with the projections are the same, the maps must also be the same. This is fine. My only problem is that I want this to work in say the category of groups as well. How can I adjust this argument to work in "sets with some more structure" categories?

[Anonymous No.15620387]

>>15620334
i finally got something right.
one last question, i know also the definition of derivative like this:
f(x+h) = f(x) + f'(x)h + o(x)
this is why i said "1 is too big of a time difference". so my question is: i can calculate the change of position with only the derivative only if h is very very small? otherwise i have to do the integral

[Anonymous No.15620654]

Is there a treatment for hemochromatosis that isn't just dressed up blood-letting?

[Anonymous No.15620793]

>>15618306
Note that you can equally represent a sine wave as a sum of an infinite number of triangle waves (or square waves or sawtooth waves or whatever). If you're suggesting that a sine wave has a frequency (because its Fourier series has a single non-zero component) while other waveforms don't (because they need multiple sine waves), you're wrong. The sine wave isn't sacrosanct.

Any periodic function has a period, and thus a frequency (which is the reciprocal of the period; if something occurs every 0.2 seconds, it has a frequency of 5 Hz).

[Anonymous No.15620794]

>>15620387
That's not the definition of the derivative, it's an equation using it. I'm not clear what o(x) is meant to represent unless it's an error term depending on both x and h.

[Anonymous No.15620843]

excuse my retardation, but how the fuck can this be an exact sequence? when is [math]exp(2\pi i f(z))[/math] ever zero??

[Anonymous No.15620853]

>>15617247
>Shows how bad the Red Scare

with good reason. fuck the commies. shame oppie coudnt convince the government tho

[Anonymous No.15621040]

Where it says "a/e=b/f then (14.25) and (14.26) are not independent" is a mistake right? Surely a/e=b/f=c/g is necessary for them to be not independent?

[Anonymous No.15621119]

>>15621040
[math] \frac{a}{e} = \frac{b}{f} [/math] implies [math] \frac{a}{e} = \frac{b}{f} = \frac{c}{g} [/math]
let [math] k = \frac{a}{e} = \frac{b}{f}[/math]
[math] \displaystyle
k(e \alpha + f \beta + g) = a \alpha + b \beta + kc = 0 = a \alpha + b \beta + g \\
g = kc \\
\frac{g}{c} = k = \frac{a}{e} = \frac{b}{f}
[/math]

[Anonymous No.15621123]

How do I show that P(E) >= 0 for all E and [math]P (∪Ei) = ∞∑P(Ei) [/math]? P(S) was relatively simple to solve but I'm stumped on this.

[Anonymous No.15621140]

>>15621119
oh well i fucked that up somehow but you get the point

[Anonymous No.15621145]

>>15621123
err and [math]i=0\:to\:\infty[/math]

[Anonymous No.15621180]

>>15621040
14.25-6 is just a matrix equation acting on the vector (alpha, beta) to produce (c, g). For there to be an (alpha, beta) that solves the equation it doesn't matter what (c,g) is, it matters if the matrix has an inverse. If the determinant af - be=0, the matrix has no inverse.

[Anonymous No.15621334]

>>15621180
>For there to be an (alpha, beta) that solves the equation it doesn't matter what (c,g) is, it matters if the matrix has an inverse.
thats not exactly true, theres still a 1-dimensional family of solutions even if theres no inverse.

[Anonymous No.15621550]

>>15614470
bump

[Anonymous No.15621572]

>>15618306
if you wanted to be more precise but not be autistic you would just say that the fundamental of the traingle waves posted are 1 & 2 hz.

[Anonymous No.15621696]

>>15621334
Not really. (14.25) and (14.26) are both equations for a line in the alpha beta plane. If the determinant vanishes the two lines have the same slope, and they never intersect unless you tune c and g such that the two lines are identical (that is your family of solutions). But if c and g are tuned like that then the differential equation 14.24 is trivial.

[Anonymous No.15621726]

>>15615142
>DNA denialism
That's a new one on me.
A little confused but he asked a few interesting questions.

[Anonymous No.15621962]

how does one deal with a family member or close friend with pseudoscientific beliefs due to religion
or other reasons?

its getting hard for me to stay quiet when someone claims microwave ovens cause cancer or some sort food is bad for health like onions or garlic etc

[Anonymous No.15622048]

>>15620853
back to /pol/, retard

[Anonymous No.15622057]

>>15621962
ask them why they think those things. like, “what makes you think microwaves cause cancer?”, “do you think anyone at a university has ever tried to see if microwaves cause cancer?”. after a few of those itll become apparent that the person believes the illuminati wants everyone to own a microwave and get cancer or something retarded like that. at this point, you have to convince the person that they arent living in a movie and that hiding information about a ubiquitous household appliance from every academic institution on the planet is probably impossible.

[Anonymous No.15622213]

>>15620793
>The sine wave isn't sacrosanct
Lmao. Complex exponentials (and by extension sin/cos) are eigenfunctions of linear ODEs and have a unique relationship with differentiation and integration that isn't shared by other waveforms. Just because you can construct them from other waveforms doesn't detract from their fundamentality. Sure, you could do shit with an infinite series of square waves in place of the fundamental trig functions, but in the end you are still relying on their unique properties, just in a roundabout way. That's like saying [math] \Gamma(z) [/math] isn't fundamental because [math] \Gamma(z) + \sum_{n=0}^\infty A_n \sin(n \pi z) [/math] are all equally valid extensions of the factorial. I understand what you're getting at and you're not entirely wrong, but to try to claim the standard trigonometric functions aren't sacrosanct compared to other arbitrary basis functions with the same fundamental frequency is nonsense.

[Anonymous No.15622539]

i think we’ve lost the plot here. the anon was asking what frequency the triangle wave had, and we somehow ended up discussing orthogonal function spaces.

[Anonymous No.15622603]

look man idk that triangle wave looks like it has a pretty consistent wavelength, and thus period, and thus frequency
unless we're also going to argue that something like [math]\cos{x}+\cos{2x}[/math] has a frequency other than [math]\frac{1}{2\pi}[/math], since it actually alternates between that and [math]\frac{1}{\pi}[/math] when you break it down into its components

[Anonymous No.15622760]

>>15599798
Any /Med/ experts here?
So I have found a source of cheap tirzepatide from china, lab testing show it is legit and pure stuff. So my thinking was to take mk677 5-10mg (GH secretagogue) before bed + GW501516 ("endurobol") 10-20 mg/day when I feel like adding it in for a few weeks. Bought an autoinjector (picrel) I will use to inject the mounjaro 1x a week. all of this is to get me to get close to 10% bodyfat the easiest way possible, limit muscle catabolism and allow me to recover and keep up with muay thai sessions, cardio and lifting WITHOUT having to fuck with injecting T and SARMs etc.
Sidenotes: Thinking about getting a continous blood glucose monitor.
P5p vit B6 in order to keep potential prolactin issue in check.
Any advice to a human labrat or why it would be a terrible idea?

[Anonymous No.15623097]

>>>/adv/29498528

[Anonymous No.15623249]

>>15622213
not everything that happens periodically is best represented with sin and cos. the path traced by something bouncing between two surfaces would be a triangle wave. that's not any more or less inherent than a point going around a circle.

[Anonymous No.15623396]

Hey! I've got a problem that I've managed to kinda get right, but it's probably not a very respectable way of reaching the answer. So, we have a function f(x,y)= x^y, when is the partial derivative for x and y equal? I managed to get 1=xlnx by turning the Fx = x^(y-1) as x^y/x but I feel as if it's not really the answer even though it is to where x > 0. Thanks

[Anonymous No.15623592]

>>15620843
>when is exp(2πif(z)) ever zero??
Never. They meant the multiplicative group, so the identity is the constant function 1. Then it should be clear that the sequence is exact.

>>15621123
[math]P(E) \geq 0[/math] follows from [math]e^{-x} > 0[/math]. The sum property follows from the linearity of the integral.

[Anonymous No.15623594]

Why people kill themselves? Aren't it stays against the nature?

[Anonymous No.15623621]

>>15623594
Humans ate from the tree of knowledge of good and evil and became more like gods

[Anonymous No.15623629]

>>15623621
Why I love hugs so much?

[Anonymous No.15623635]

>>15623592
>They meant the multiplicative group
Yeah that makes sense. Thank you anon I love you

[Anonymous No.15623678]

>>15618870
Another question I'm a bit stuck on, would really appreciate help on part c)

[Anonymous No.15623682]

>>15623678
heres the markscheme

[Anonymous No.15623693]

>>15623396
also got y=xlnx. why do you think you're wrong?

[Anonymous No.15623718]

>>15623621
Animals do too. Even my own doggo kept trying to drown herself in her bowl when she was getting radiation for brain tumour.

[Anonymous No.15623721]

>>15623693
It's just I don't like the answer being 1 = xlnx when I do it, like what is 1? Can you please show me your process? Thanks!

[Anonymous No.15623757]

>>15623721
guess there is an issue, i get y=xlnx, you somehow lose the y.

[Anonymous No.15623846]

If alpha and beta are roots of the equation of x^2 + (3^1/4)x + 3^1/2 = 0, then the value of alpha^96(alpha^12 - 1) + beta^96(beta^12 - 1) is...

Do we have to do something like this ?
Alpha^12*8(alpha^12 - 1) ???


Please help on how to develop the thought process to solve these type of problems ?

[Anonymous No.15623853]

>>15623846
We don't have to find the exact value

The option in answers are given as
A) 52*3^24
B) 56*3^24
C) 56*3^25
D) 28*3^25

Do we have to reverse engineer the options to find answer ???

[Anonymous No.15623860]

>>15623678
>>15623682
The series expansion of [math](1 + x)^n[/math] only converges when [math]|x| < 1[/math]. You should have been taught this if you are studying binomial expansion.

In the question that means [math]|2x| < 1[/math], but this isn't true when x = 3/4 so it diverges.

[Anonymous No.15623862]

What are the limits of sexual dimorphism? Remember that meme about JRPG sexes vs. Western RPG sexes? (I can't find it anywhere now) Is it possible to have ultra feminine women and ultra masculine men within the same stock?

[Anonymous No.15623963]

>>15623862
angler fish are freakin crazy

[Anonymous No.15624037]

>>15623860
I think I get it now, thank you sir.

[Anonymous No.15624099]

Hi, I'd like some help with b), please

My method to solving it was this:
When A finishes 1st there are, 7! ways of arranging them so that J finishes after A,
If A finishes in 2nd place there are, 6! ways J can finish behind A. Don't multiply by two since one of them is included when A finishes first
A=3, 2!*5!,
A=4, 3!*4! and so on result: 7!+6!+2!5!+3!4!+4!3!+5!2!+6!
My answer is wrong, and I don't really understand where in my thought process I went wrong.

[Anonymous No.15624102]

>>15624099
I understand method 1
I don't understand method 2, if someone could explain that to me that would be super, thanks.

[Anonymous No.15624259]

>>15624099
> If A finishes in 2nd place there are, 6! ways J can finish behind A
This is where you went wrong. There are are 6 places J could finish and 6! ways the other runners could be arranged (remember that one of the other runners must now come first, or first and second when A finishes 3rd). So you had the right idea, but the wrong combinations. Your sum would then be 7x6! + 6x6! + 5x6! + ... which is the method use in method 2.

[Anonymous No.15624604]

>read lecture notes
>wtf is this man talking about I have zero clue what this means
>I'm way too dumb for this
>step away and have a snack and coffee
>slowly read through the notes
>check every step and computation on paper
>mfw it was easy all along

[Anonymous No.15625021]

>>15623592
Oh yeah linearity of integral makes perfect sense. But could elaborate more how to show that [math] P(E) \geq 0? [/math]

[Anonymous No.15625501]

>>15623846
Bump, pls help

[Anonymous No.15626474]

>>15624102

Just think about J and A, ignoring everyone else. For every finishing position of J and A, the remaining 6 runners can finish in any permutation = 6!. So, we just need to think about all of the ways in which J may finish after A. For each one of those, we multiply by 6!. For example, if A is 2nd and J is 4th, we have 6! possible ways for the other runners to finish.

We just need to count all of the "J after A" permutations systematically.

Suppose A finishes first. J may finish 2,3,4,5,6,7,8 (i.e. there are 7 possible positions for J). For each of those finishes, the other 6 runners can be in any permuation = 6!. So, there are 6! * 7 possibilities when A finishes first. [7*6!]

If A finishes second, J may finish 3,4,5,6,7,8. Again, for each of those finishes, the other 6 have 6! permutations. So that's 6 finishes for J with any of the 6! permutations of the other runners. [6*6!]

If A finishes third, J may finish 4,5,6,7,8 etc. > [5*6!]

A:4th > J:5,6,7,8 > [4*6!]
A:5th > J:6,7,8 > [3*6!]
A:6th > J:7,8 > [2*6!]
A:7th > J:8 > [1*6!]
A cannot finish 8th, since J must be behind her.

Add it all up: 6!*(7+6+5+4+3+2+1) = 6!*(28) = 20160

[Anonymous No.15626641]

>>15623846
>>15625501

Rearrange:
[math]x^2 + 3^{1/2} = -3^{1/4}[/math]

Square both sides:
[math]x^4 + 2*3^{1/2}x^2 + 3 = 3^{1/2}x^2 [/math]

Simplify:
[math]x^4 + 3 = -3^{1/2}x^2[/math]

Square again:
[math]x^8 + 6x^4 + 9 = 3x^4 /implies x^8 + 3x^4 + 9 = 0 [/math]

Knowing that a and b are solutions of the original, they must also solve this equation. Hence:

[math]a^8 + 3a^4 + 9 = 0 /implies a^8 = -3a^4 - 9 [/math]

We need an expression for a^12, so let's try:

[math]a^12 = -3a^8 - 9a^4 = -3[-3a^4 - 9] - 9a^4 = 27[/math]

!!!!

So, our desired expression is 27^8(27 - 1) + 27^8(27-1) = 52(27^8) = 52 * 3^24, which is answer a.

Ugly problem. Not sure there was an easy way, but it seemed fruitful to proceed with the initial steps because you get that cancellation. So there's a general form:

[math]x^2 + px + p^2 /implies x^2 + p^2 = -px /imples x^4 + 2p^2 + p^4 = p^2x^2[/math] and you can cancel the x^2 term on the LHS, which makes it easier. Maybe not a typical approach to these sorts of problems - I had to play around with it.

[Anonymous No.15626653]

>>15626641
Sorry, my LaTeX wasn't great because 'implies' is not part of the core library.

If it's not clear, I can write it up again tomorrow.

[Anonymous No.15626882]

>>15626653
>'implies' is not part of the core library.
But it is.
[eqn]x \in \emptyset \implies x \not \in \emptyset [/eqn]

[Anonymous No.15626910]

>>15600828
Damn, 4chan is a cruel mistress

[Anonymous No.15627135]

>>15623846
>help on how to develop the thought process to solve these type of problems
Assuming you're not supposed to actually compute the roots and use their values to solve it (which is rather easy to do), I have no idea, man. I feel like you just gotta do trial and error and get lucky.

Got a similar (?) idea as the other anon. Separate the [math]3^\frac{1}{2}[/math] and square both sides:
[eqn]x^2 + 3^\frac{1}{4}x + 3^\frac{1}{2} = 0 \implies x(x + 3^\frac{1}{4}) = -3^\frac{1}{2} \\ \implies x^2(x^2+2\cdot3^\frac{1}{4}+3^\frac{1}{2}) = 3.[/eqn] Now, since [math]x^2 + 3^\frac{1}{4}x + 3^\frac{1}{2} = 0[/math], the thing inside the parentheses simplify to [math]3^\frac{1}{4}x[/math], so we have
[eqn]x^2(3^\frac{1}{4}x)=3 \implies x^3 = 3^\frac{3}{4}.[/eqn] From this we're able to calculate [math]x^{96}=3^{24}[/math] and [math]x^{12}=3^3[/math] which you can plug into your shitty expression since this is true for both alfa and beta.

[Anonymous No.15627262]

>>15625021
It's the monotonicity of the integral. Since [math]e^{-x} \geq 0[/math] everywhere, we have [math]\int_E e^{-x} \ dx \geq \int_E 0 \ dx = 0[/math] for all E.

[Anonymous No.15627417]

Today at work I splashed myself with some 30% potassium hydrate Ph up and I still feel bruised on the left side of my face, half my mouth and cheek feel lumped up. I did manage to rinse it in a matter of seconds but the damage is done. What exactly did it do to me and is there any way to make it better? Thanks
>it would hurt really bad for me right now if I did picrel

[Anonymous No.15627935]

>have 5 colors of balls
>there are an infinite number of them, evenly distributed
>pick 10 at random
what are the odds that i get 0 of one color? I know how to get specific outcomes (ie [math]\binom{5}{5}\binom{5}{3}\binom{5}{1}\binom{5}{1}\binom{5}{0}[/math] but enumerating that for each arrangement (ie 4,4,1,1,0) etc seems tedious as hell

[Anonymous No.15628058]

>>15627417
msds says “notes to physician: treat symptomatically” so youre fine.

[Anonymous No.15628196]

>>15627417
you got an instant chemical burn. Glad you rinsed it quickly, but you are correct, the damage is done. What happened was it neutralized on contact with your skin, primarily reacting with the fat in them, releasing a large amount of heat, which burns your cells.
Ways to make it better would be like treating any other chemical burn. Don't put on any moisturizers, it will burn more. I believe certain oils, not creams, will help, but I've never done chemical burn aftercare before.
Sorry to hear you have to deal with this, get well soon. Hopefully you can stay safe at work moving forward

[Anonymous No.15628476]

I thought I figured out EM interaction. But maybe not.
I envisioned it as coming only from the movement of charged matter. So for example, two positively charged things that are repulsing each other and are repulsed by outside charges so they completely stationary.
If I were to jerk one of these things away from the other, the other would feel less of a repulsion in that direction and would move in that direction. And that is how energy is transferred.
Same thing if I jerked the thing towards the other thing. It would feel a greater repulsion and move in that direction.
The EM interaction, the transfer of energy, the photon exchange, is all based on this. And the polarization of wave is just the direction of the changing amount of repulsion.

That makes sense. But I was also thinking about how electrons in atoms can absorb and emit EM radiation that changes their energy level. I assume electrons are stationary and are still the same charge, so how could they effect the EM field to create a photon?

[Anonymous No.15628676]

Not sure which channel to post this in but how do you do this? I've already shown 4|P so just need to prove 3|P

[Anonymous No.15628706]

>>15628676
pigeonhole principle
you have 4 variables, and 3 possible values mod 3. two of them must be congruent mod 3, then, and so their difference will be divisible by 3

[Anonymous No.15628715]

this is probably a retarded question, but
>have a test with 14 trials
>there are 6 options, all of which can be repeated infinitely (so between 0 and 14 instances)
How can I calculate the probability that each color will be drawn between 0 and 4 times? ie you could have
>4 4 4 2 0 0
>4 4 4 1 1 0
>4 4 3 2 1 0
etc

I think the total number of ways to arrange 14 trials of 6 colors should be [math]6^{14}[/math]
And I think the actual number of ways will probably something to do with stars and bars, but I'm not sure.

[Anonymous No.15629228]

>>15628476
You start by stating moving charges create an em field, okay, but then claim "the EM interaction, the transfer of energy, the photon exchange, is all based on this". You are confusing cause with effect.

> so how could they effect the EM field to create a photon?
Because your hypothesis is wrong. Any number of experiments can prove it's false. You are trying to apply classical laws to a quantum system.

[Anonymous No.15629353]

Trust in my Self-righteous suicide

[Anonymous No.15629593]

>>15624259
I understand now. Thank you.

[Anonymous No.15629788]

>>15626641
Thanks anon, really appreciate it. >>15627135
Thnks you too

[Anonymous No.15630228]

What are some not-painfully-obvious examples of groups isomorphic to [math](\mathbf{Q}, +)[/math]?

Example: [math]\langle x_1, x_2, x_3 \dots \mid \forall n > 1: x_n^n = x_{n-1} \rangle[/math].
Non-example: Silly constructions a-la [math](\mathbf{Q} \oplus A) / A[/math].

[Anonymous No.15630364]

Is the combination of two partial isometries a partial isometry again? Mind that I‘m talking finite-dimensional vector space.

I tried find a counterexample but nothing works.

[Anonymous No.15630376]

>>15630364
You mean composition? If so it's true.

[Anonymous No.15630379]

>>15619805
It’s wrong. The are infinitely dimensional vector spaces that do not have an orthonormal basis. Just trust me bro. So you can find at least two vectors in every basis, such that these two are not orthogonal.

[Anonymous No.15630388]

>>15630376
Really? Yes, composition. Do it’s actually a partial isometry again. That’s remarkable. Do you have a source for that maybe?

[Anonymous No.15630396]

>>15630364
The identity map [math]I[/math] is certainly a partial isometry, but the combination [math]I+I[/math] is not.

[Anonymous No.15630398]

>>15630379
Provided ofc you‘re not looking at a specific U, but we‘re talking about any given U. In specific case this argument does not hold.

[Anonymous No.15630403]

>>15630396
Sorry, I specifically meant composition of mappings, as the other anon pointed out

[Anonymous No.15630456]

>>15630403
Oh. Well, this is also false, actually. Consider on [math]\mathbb{R}^2[/math] the orthogonal projections [math]p(x,y) = (x,0)[/math] and [math]q(x,y) = (\frac{x+y}{2}, \frac{x+y}{2})[/math]. (p projects onto the x-axis, q projects onto the diagonal.) Note that every orthogonal projection is a partial isometry. But the composition [math]pq[/math] is not a partial isometry (draw a picture and see for yourself).

[Anonymous No.15630542]

>>15630456
Thank you

[Anonymous No.15630557]

>>15630456
Huh? What are the domains of definition of these partial isometries? It can't be all of R^2 because then they'd be total isometries and they're clearly not.
>>15630388
Suppose f,g are partial isometries. We wish to prove that f.g is a partial isometry. Take x,y in the source of g. If f.g(x) is defined then g(x) is defined, and similarly for y. So if they're both defined then g(x) and g(y) are defined, and since g is a partial isometry, d(g(x),g(y)) = d(x,y). Then because f is a partial isometry, d(f(g(x)),f(g(y)))=d(g(x),g(y)). Putting those together you have d(f(g(x)),f(g(y)))=d(x,y), i.e. f.g is a partial isometry.

[Anonymous No.15630595]

>>15630557
Anon, it looks like you're taking "partial isometry" to mean "a partially defined map between metric spaces which is an isometry whenever its defined". But in the context of functional analysis, "partial isometry" means a linear map between Hilbert spaces that acts isometrically when restricted to the orthocomplement of its kernel (and one can give many other equivalent formulations). I assumed this is what >>15630364 meant.

[Anonymous No.15630606]

>>15630595
Wow, what an awful choice of name.

[Anonymous No.15630721]

What is the math behind superconductor levitation? How can you tell what the "buoyant" force is, and how much mass a certain conductor can lift?
Can a conductor even lift an external load in the first place?

[Anonymous No.15630862]

>>15630721
You are talking about the Meissner effect whereby all magnetic fields are expelled from a superconductor below its critical temperature. That math behind what you ask is complicated and I'm not aware of any model that covers it in some general manner. But it will be proportional to the strength of the source magnetic field, the shape of the superconductor, what type / material the superconductor is. Also there is a hard limit to the mass that can be lifted since superconductors also have a critical magnetic field above which they are no longer superconducting and so the effect will stop.

[Anonymous No.15630924]

how the fuck? i tried defining A*the remaning vector of the orthonormal base so that the result is perpendicular to the other one given and the norm is 12 in that direction, but it didnt work because that's stil not the maximum (gram matrix diagonalization shows it's 15).

[Anonymous No.15631073]

>>15600625
play Kerbal Space Program and it will start to make more sense

[Anonymous No.15631074]

>>15630862
>model that covers it in some general manner.
k. well if we want hovercars that aren't limited to some gay indoor magnetic tracks, some numbers would be nice.
Earth's field is 25-75 microTesla, so having some clear number to work towards as a goal (max current? rejection coefficient?) would be good for managing expectations

[Anonymous No.15631103]

biologically speaking, ignoring societal and economical pressures, what would be the optimal age for humans to have children?

[Anonymous No.15631104]

>>15600819
im pretty sure it’s apoapsis and periapsis for orbits

[Anonymous No.15631119]

>>15631104
apoapsis/periapsis are in general
apogee/perigee are specifically for Earth
aphelion/perihelion are specifically for the sun

[Anonymous No.15631138]

>>15631119
ah

[Anonymous No.15631148]

>>15631074
> Earth's field is 25-75 microTesla
Which is nowhere big enough. It's why every levitation video you have seen used a normal earth magnet which have a field in the 0.5 to 1 Tesla range.

[Anonymous No.15632109]

Might be dumb, but here's my problem :

I am numerically solving a PDE with respect to time and 1D space.
For the time part, I use forward euler. For the space part, I use some (allegedly) order 2 scheme.
I now want to experimentally check if the space scheme is indeed, of order 2, that is, using my simulation and not pen and paper. By doing so, I found that my solution is of order 1 and not 2.

My question :
Do I get a convergence of global order 1 because I am using forward euler in time , which just "eats" the finer approximation of my space scheme?
(My guess is I should implement a high order scheme for time, such as RK4, but god damn...)

I would appreciate any kind of help, please.

[Anonymous No.15632659]

I have just begun learning chemistry on my own. I found these definitions for chemical reactions.
>A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.
>A chemical reaction occurs when matter undergoes a change in its composition and/or the structure of its molecules.
Later, the lecturer spoke of mixtures, which do not result in chemical reactions. This made me reconsider what specifically constitutes a chemical reaction.
For example, burning firewood constitutes a chemical reaction as the wood transitions into a different state of matter. But what about submerging paper into a tub of water? The paper becomes soggy and tears easily, but it's still a solid. Did the paper's chemical composition change?

[Anonymous No.15632684]

>>15626474
thank you!

[Anonymous No.15632925]

>>15599798
Does anyone know a good latex package for typesetting Recursive Transition Networks, or will I just need to draw them as images with something else and then add the images to the document?

[Anonymous No.15633373]

>>15632659
too autistic, dial it back

[Anonymous No.15633554]

is it called normal force because the force is perpendicular to the object on a plane?

[Anonymous No.15633560]

>>15633554
yes

[Anonymous No.15633577]

>>15633560
is there any way we can tell scientists to change the name of normal force to anti gravity force?

[Anonymous No.15633711]

>>15633577
sometimes the plane isn't horizontal

[Anonymous No.15633875]

>>15627262
ahh yeah. Thanks a lot anon!

[Anonymous No.15634071]

why can't a point particle spin faster than light? what causality is it violating if it has 0 volume?

[Anonymous No.15634077]

>>15634071
Nobody talks about relativistic spinning point particles except in the context of quantum mechanics. There is no problem with a point particle having spin, and there is no causality principle it is violating.

[Anonymous No.15634092]

>>15634077
im asking a FTL question. we say spin isnt real physical spin because it cant be because the particle would need to be spinning faster than light. and i can understand how that would cause problems if a particle were made up of subparticles because they would have to move in physical space. but when a point particle spins, does it really move in 3d space? what part of it is moving where? couldnt then a point particle have different rules about how fast it can spin?

[Anonymous No.15634111]

>>15633711

okay

[Anonymous No.15634114]

>>15634092
> we say spin isnt real physical spin because it cant be because the particle would need to be spinning faster than light
Spin is real angular momentum. It can be converted to orbital angular momentum which no one has any problem associating with real spinning. There is no problem within relativistic quantum mechanics with a particle having spin. But if you want to deal with this you need to consider it quantum mechanically, which you clearly aren't doing.

[Anonymous No.15634127]

>>15634092
>but when a point particle spins, does it really move in 3d space?
Yes spin is definitely connected to 3d space, because you can always identify a definite axis about which the particle is spinning (even quantum mechanically). This axis rotates the normal way under spatial rotations. This is how we know spin is really angular momentum connected to physical space rather than something purely internal.

[Anonymous No.15634131]

>>15634127
but if its pointlike then the particle doesnt occupy any space. you can imagine an axis inside of a generic sphere and just call it pointlike but its not really pointlike if you are thinking of a sphere.

[Anonymous No.15634605]

>>15634092
'spin' is simply a label, nothing is spinning so talking about faster than light rotation is meaningless. It's an intrinsic property of the particle just like charge is but not one ever seems to get stressed by the charge density of a point-like particle being infinite. All this confusion comes about because physicists are bad at naming things. It's not always their fault since many things were observed before being understood: "this result we measured appears as if the electron is spinning, lets call it spin"

[Anonymous No.15634984]

>>15634092
It's like spin in some ways but not others. Whether you call it real spin or not is really just a choice of definitions.

[Anonymous No.15635393]

>>15634605
its only a label because we know the magnetic moment of an electron is too high for physical spin to create it because the electron would have to be spinning faster than light. all this shit about its not really spinning its actually quantum whatever is all attempts to explain why it has more magnetic moment than a particle of its size can spin. im saying, lets stop thinking of bullshit to explain why it has to not be spinning and start asking under what conditions could something spin faster than light and not violate causality.

[Anonymous No.15635457]

>>15634605
>nothing is spinning
sophism moment

[Anonymous No.15635466]

>>15635393
> electron would have to be spinning faster than light
Even if the electron was a spinning object that still wouldn't be true. The laws of relativity still apply and you would have to apply them to a rotating reference frame.

>>15635457
Nice, I chuckled.

[Anonymous No.15635485]

>>15635393
Well 100 years of experimental evidence and more complete theories of physics would indicate you're wrong. Just saying.

[Anonymous No.15635512]

>>15635485
no shit. no shit that the prevailing idea is "it cant be spinning faster than light". thanks for the input, genius. now maybe try thinking up a reason why it could. the possibility in my mind is based on the idea that while 3d objects cannot move faster than light maybe 2d or 1d objects can. or perhaps spinning is fundamentally different to linear motion. perhaps it does not violate causality within itself because no part of it is communicating with any other part of itself because it isnt a 3d object.

[Anonymous No.15635822]

Does every finitely dimensional vector space have a „standardbasis“?

[Anonymous No.15635852]

Biology question:
Can fetishes be hereditary?

[Anonymous No.15635865]

>>15635852
I doubt anyone's done the studies to find out. Don't see why it wouldn't be possible in principle though.

[Anonymous No.15635879]

>>15635865
i bet somebody has done a study on whether blacks like big butts because socialization or not

[Anonymous No.15635882]

Given a cardinal k, what's the name for a topological space in which every union of <k opens is open? I think the category of these should have a lot of the same nice properties as the category of topological spaces.

[Anonymous No.15635908]

>>15635512
> while 3d objects cannot move faster than light maybe 2d or 1d objects can
there's no longer reason this would be true, the number of dimensions does not matter.

[Anonymous No.15635949]

>>15635512
> while 3d objects cannot move faster than light maybe 2d or 1d objects can
there's no logical reason this would be true, the number of dimensions does not matter.

[Anonymous No.15635978]

>>15635949
its not a matter of logic, it might just be true about objects. as far as i know 2d and 1d objects are hypothetical, we dont really have any 2d objects we can identify, but if any were going to exist, they'd probably be the most fundamental particles. and weve seen before that the more complex structures can be formed out of more fundamental structures that have completely different apparent physics(quantum/non quantum scales). so it could be that our large scale 3d objects and 3d interactions are limited by c, but maybe the constituent particles are not.

but its more compelling to me to ask whether spinning is different to linear motion. because the real sticking point is it cant communicate with anything faster than c. which is a problem with linear moving particles because they actually hit other shit and have to communicate with them. but if an object is just spinning in the middle of no where, what opportunity does it have to communicate? especially if its a 2d object. its insides arent moving at all due to not having insides. the surface could also be thought of as not moving at all relative to itself.

[Anonymous No.15635993]

Why are advanced, mathematician-oriented mathematics textbooks so terse and devoid of exposition or motivation? This sounds like a loaded question that just sets up a rant, but I'm serious. I'm starting to suspect that my background (electrical engineering and physics) might have not provided me with the foundations to actually read and understand mathematical texts.

In my experience, I've found I learn material much deeper, faster, and at a much more intuitive level when I can see how and why some mathematical formula or technique was created, and critically, the thought processes and failures leading to the (often unspoken and unseen) core milestones of those who were blazing the trail. In fact when math is presented to me this way, the proofs and such almost feel self-evident, along with what leads to dead ends or pointless toil (Strogatz's Nonlinear Dynamics and Chaos comes to mind)

and yet from the books I've tried to read, it seems like mathematicians try their absolute best to snub those details from existence, as if they're doing their damnedest to force the illusion that they were endowed with the proofs and techniques by divine provenance

Is there a kernel of truth to that or am I just telling on myself here?

[Anonymous No.15636028]

>>15635993
https://calculusmadeeasy.org/prologue.html

[Anonymous No.15636039]

>>15635978
>>>/x/

[Anonymous No.15636061]

>>15636039
you could be telling me "no, we know 2d objects of 1d objects exist and here they are and we tested them and no, they cant move FTL, or spin FTL"
the only 2d object i know of thats even theorized is one view on black holes where they have no inside, they just exist as the event horizon as a 2d surface.
you could be telling me all of them that weve ever seen were not rotating FTL.

[Anonymous No.15636090]

>>15636061
What are you looking for crazy solutions to a problem that doesn't exist? A 1d or 2d spinning object wouldn't explain things like the Stern-Gerlach experiment, the Quantum Hall effect, Cooper Pairs, the anomalous Zeeman effect and a whole swathe of other experiments and observations.

[Anonymous No.15636144]

>>15636090
because it seems like were missing out on a whole host of questions and possibilities because we are assuming the FTL rule precludes particles spinning like large scale counterparts.
when they were sussing out particle spin, and discovering it couldnt be spinning that fast, what experiments did they do to prove it definitely wasnt spinning faster than light?

[Anonymous No.15636177]

>>15636144
Let me guess. Your physics education consists of a pop-sci book or a few YT videos.

[Anonymous No.15636193]

>>15636177
yes~ now educate me please(i'm lying). so terrible someone wanting knowledge. i asked you what experiments were done to prove it wasnt spinning FTL. i dont know the history of the experiments. perhaps there were hundreds that checked this.

[Anonymous No.15636206]

>>15636193
It's simply defined not to be spinning, because there's no point that actually moves as if it was spinning. You could define it as actually spinning and nothing would change.

[Anonymous No.15636213]

>>15636193
> All of quantum physics and quantum field theory.
Get someone else to spoon-feed you you moron.

[Anonymous No.15636238]

>>15636213
so you dont know, you just assume the science communicators you listen to are right that it cant be spinning FTL.

[Anonymous No.15636255]

>>15636238
What do you mean by spinning FTL? What experiment could tell you that even in principle? Experiments tell you physical facts, not definitions of words.

[Anonymous No.15636313]

>>15636255
i dont remember reading anywhere that they cant prove an electron doesnt spin FTL. are you telling me they didnt run any experiment to figure that out, they just assumed it because they believe that hard in the noFTL rule?

[Anonymous No.15636325]

>>15636313
A point cannot spin because it spinning it wouldn't move any part of it, so it would be the same as it not spinning. FTL has nothing to do with it.

[Anonymous No.15636342]

>>15636325
i cant believe nobody every ran an experiment that somehow confirmed it doesnt rotate FTL. people regularly run experiments which reconfirm relativity, its not somehow below scientists to check. are you telling me they have no idea how to check that?

[Anonymous No.15636355]

>>15636342
How would you check that? Until you propose an experiment your ideas are falsifiable and meaningless. Have they ever confirmed it doesn't glorblebargle blurstierly than blackleblickle?

[Anonymous No.15636364]

>>15636355
im asking you. im asking you whether to your knowledge we have any of those experiments?
if i find out that nobody could ever think of such an experiment, then i will try to come up with such an experiment. im not trying to think of one because i assume somebody with a particle accelerator had a much much better way to check.

[Anonymous No.15636380]

>>15636364
I don't think the idea that it's "really spinning" makes any predictions different from the conventional theory that you could use to check.

[Anonymous No.15636387]

>>15636380
since you dont even know of an experiment that confirms that i dont have high confidence youve explored its implications. it would be pretty big news to find something moving FTL at all. maybe its like the microscopic extra dimensions idea and it will never have macroscopic FTL effects, but it would still be huge news to find out c isnt a universal limit.

[Anonymous No.15636392]

>>15636387
What part of it would move ftl if it was spinning? It's a point so there's no part of it that isn't the centre, and the centre doesn't move when you spin something.

[Anonymous No.15636401]

>>15636364
Because every experiment that agrees with QFT, like CERN, disproves your conjecture. We already have theories that explain all the quantum properties of nature. Spinning fundamental particles is an idea that died along with the 19th century. Such objects would have so much (rotational) self-energy they would be spewing out radiation all other the place. What you have is a hypothesis that doesn't agree with the data. Back to school son.

[Anonymous No.15636404]

What is the mechanism behind the Bohm-Aharanov effect? How can force be applied to a charged particle in a region devoid of EM force fields? How is it transmitted?

[Anonymous No.15636412]

>>15636401
tell me more about what the particle would be doing if it were spinning ftl?

[Anonymous No.15636426]

>>15636404
that's the paradox
you must accept that the 4-potential (φ, A) is physically real or reject local realism

[Anonymous No.15636442]

>>15636412
Any charged object spinning, i.e a dipole, would gradually lose energy due to emitting EM radiation.

[Anonymous No.15636465]

>>15636442
the speed of the spin changes how much energy it loses over time? what if there are speeds where it becomes stable?

[Anonymous No.15636494]

>>15636465
The speed, ftl or otherwise, is irrelevant. if say an electron was non-zero in size and was physically spinning it would act as a classical dipole and gradually lose energy. The alternative is a point-like particle, which clearly can't be physically can't be spinning, having an intrinsic magnetic moment. Only the latter agrees with experiment.

[Anonymous No.15636522]

>>15636442
Not true. Electrons in atomic orbitals other than the first have non-zero orbital momentum but can't lose it by emitting radiation if the lower orbitals are full.

[Anonymous No.15636536]

>>15636522
Well, yeah, and that's why quantum mechanics was invented to explain it. It's why orbiting electrons don't lose energy and collide with the nucleus. In my example I was talking about an isolated particle in free space.

[Anonymous No.15636708]

>>15636442
do you know why this is true? or are you pulling macro phenomena out of your ass and treating them as fundamental?

[Anonymous No.15636761]

How difficult would it be to alter a plant's genes to, for example, change the color of its leaves and flowers? is it even possible? Can CRISPR do it?

[Anonymous No.15636826]

>>15632659
>>15633373
I continued consuming material but I still don't understand. I will try to be more concise.
What happens to paper when it's submerged in water? Is it a chemical reaction?

[Anonymous No.15636850]

>>15636826
it causes a physical interaction not a chemical reaction. the cellulose fibers that make up the paper dont combine or exchange atoms with water, they just sit next to each other. paper falls apart in water but not because there was an exchange of atoms, but just because all paper is is fibers of cellulose that are smushed together and dried. like when spaghetti dries it gets rigid. when you wet it again the fibers can physically pull apart like wet spaghetti.

[Anonymous No.15637448]

I keep getting the wrong answer but I'm, not sure what I'm doing wrong:
y'+2xy = 0
y' = -2xy
1/y * y' = -2xy
1/y dy = -2x dx
ln y = -x^2 + c
y = e^(-x^2+c)

But the correct answer is supposed to be Ce^-x^2!

[Anonymous No.15637471]

>>15637448
I'm retarded man, it's:
y'+2xy = 0
y'*e^x^2 + 2x*y*e^x^2
y*e^x^2 = C
y=Ce^x^2

[Anonymous No.15637475]

>>15637471
-x^2 but you get the point

[Anonymous No.15637761]

This is giving me an aneurysm, how do you re-draw this to make figuring out the equivalent resistance easier?

[Anonymous No.15637941]

>>15637761
Label the two nodes that have the diagnonal wires. The 15+10, 10+40, and 20+30 are all in parallel.

[Anonymous No.15638131]

This isn’t a question nor is it stupid, but I didn’t want to make a thread for it - I’ll just throw it out in the void.

If someone could develop a paint that changed color according to temperature, that would be really useful. Black when it’s cold, white when it’s hot. I want my roof to be black when it’s cold and white when it’s hot. Make it happen universe

[Anonymous No.15638140]

>>15638131
pretty sure we do have those paints but i dont think they survive weathering well.

[Anonymous No.15638214]

Disclaimer: I'm completely ignorant of the world of research, never been to a University.
I was reading some papers yesterday and was wondering why citations are considered to be so important, some of the papers had been debunked – the most recent citations were from recent papers talking about how wrong the initial one was – but it makes me wonder why we consider citations as important at all.
Seems like some very naive indicator to use, am I wrong? Science as a practice seems very weak in the end.

[Anonymous No.15638220]

>>15600832
heated carbon rod
enclosed space
breathe

[Anonymous No.15638223]

>>15635882
>every union of <k opens is open
Bro, that follows from the definition of a topological space.

[Anonymous No.15638284]

>>15638214
>Science as a practice seems very weak in the end.
you know how some science people are unbearably pedantic? they need to be precisely right and it drives them crazy when someone is just a little bit wrong? makes scientists fucking unbearable right?
they do that with each other.
scientists are constantly trying to prove each other wrong. thats why science is strong.
as those citations fall so does the strength of the paper and it *should* lose strength as the citations lose strength.
it isnt even necessarily the fault of the researcher who used those citations, it could possibly be valid thought based on false premises and we are thankful the premises got proven wrong because otherwise the conclusion in the paper might still seem to make sense.

[Anonymous No.15638295]

if somebody proves einstein wrong scientists are not going to be like OH NOES MY SCIENCE BIBLE IS WORTHLESS NOW. they're going to be like "a whole new era of physics to discover!"

[Anonymous No.15638297]

>>15638223
Oh, whoops. Intersection, not union.

[Anonymous No.15639368]

I want to learn computational chemistry.
Am I right in thinking you should start with Hartree-Fock first, then the rest (whatever this is https://en.wikipedia.org/wiki/Vienna_Ab_initio_Simulation_Package)) should some easy?

[Anonymous No.15639604]

>>15600625
idk exactly how it works but in ksp it kind of rotates your orbit. so the actual effect depends on the shape of your orbit and where you are in the orbit.

[Anonymous No.15639617]

>>15635993
also EE person here, i agree. I had a really hard time understanding integrals in my math class. but then when i learned how integrals can be used in engineering and physics problems, the concept became a lot clearer.

[Anonymous No.15639624]

>>15638140
Well obviously I’m talking about a paint that would be good to apply to asphalt shingles. Paint is a misnomer anyway, maybe I should have said coating. https://www.rhinoshield.com/ Is an example of a better-than-paint solution, but still I don’t want to paint my roof white, because I live in a northern climate and get a lot of snow in the Winter, so a black roof is beneficial. But if it was white in the summer I wouldn’t even ever use my air conditioning

[Anonymous No.15639632]

The derivative of a cdf is a pdf. What is the derivative of a pdf?

[Anonymous No.15639713]

Can someone help me understand where this method for calculating equivalent duct diameter came from? (This is ffrom AMCA 201-02 (R2011))

I know for the equivalent diameter of rectangular ducts in determining size equivalency is given by Huebscher's equation, but this is significantly different and I assume it's due to the two different applications of the two equations?

[Anonymous No.15639753]

how good is the solubility of paraffin wax in kerosene etc? is a concentration above 10% too much to ask for? if it requires heating to dissolve, will it stay in solution or get fucked up once it goes back to room temperature?

the background is that i'm planning to make my own bike chain lube, a petroleum-based "wet" lube but with wax added to it, inspired by liquid wood/floor wax such as howard feed-n-wax

i was thinking these ratios, which has a highish wax and orange oil concentration in hope of enhancing the cleaning and lubing effect for bike chain purposes

20 ml hydraulic mineral oil
15 ml paraffin/lamp oil (like kerosene but less smelly)
5 ml orange oil (90%+ limonene)
6 g paraffin wax
4 g beeswax
(some PTFE powder too)

[Anonymous No.15639884]

>>15639753
should be miscible, i.e. 100% soluble
might precipitate out, might not, do a quick experiment to check

[Anonymous No.15639967]

>>15639884
ok thank you very much
do you know about the PTFE powder? other bike anons have asked about it too. supposedly it doesn't really dissolve in any normal stuff. does it sound ridiculous to just put some PTFE powder into ordinary chain lube and mix it with glass beads in the bottle so it's maybe not actually dissolved but you get like "sprinkles" of PTFE onto the bike chain?

[Anonymous No.15640077]

next thread, please

[Anonymous No.15640376]

I dont understand how actually find a vector that is not part of this span. I know this set of vectors creates a plane in 3D space like a sheet. You could probably just guess because the bottom component are the same so you just need a different z component? But I want to know how to actually find a vector not in it. Cross product of the span? But I thought you can only do that on square matrix's?

[Anonymous No.15640924]

>>15639368
Sort of? Hartree-Fock is intractable in practice. VASP uses density functional theory to reduce the computational cost.
>Materials Modeling using Density Functional Theory by Feliciano Giustino
is a nice textbook about the theory of DFT, it's from a physics perspective but you can see how much would be useful for a chemist in picrel.
For using any DFT software you'll also need a firm grasp of the Linux command line. If you aren't a Linux user head over to >>>/g/fglt/ and follow the links in the OP.

[Anonymous No.15641166]

>>15640376
Very easy. Take just one of the vectors, (-4,1,1)
for example. Of all scalar amounts of this vector
c * (-4,1,1) for scalar c, give something that makes
it impossible, like (-4,1,2). As a result, (-4,1,2)
is not in the linear combination of both given
vectors.