Thread 16724182

/sqt/ - simple questions thread (aka /qtddtot/)

Previous thread: >>16683085

>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?
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:
>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

Is it retarded to get a STEM bachelors to be more employable even though your passion is outside of STEM?

>>16724679
The answer for any extremely broad question like this is always going to be "it depends."

My advice for you is to only do this if you actually have an aptitude and interest in some STEM subject. I've known quite a few people go to college for CS just because of the lucrative job market, only to find out that they aren't good at programming and they don't care about computers, and then their degree is essentially a $40k piece of toilet paper.

If you're go to college to study something that you hate you'll never get good enough at it to find employment in that field and even if you do you'll hate doing that job, and you probably won't even have time for music/art/jacking off/whatever else your "passion" might be.

>>16724711
I think my talent is average, and my interest is genuine. It's just, I'd rather be remembered for writing a great novel. I just know that you don't really need to go to college to write a great novel. However, having good income while your writing makes no money is a very good thing.

If science is so important to society, why do people like Terence Tao make less money than Brad Pitt or LeBron James?

>>16724976
Importance does not equate to market value. For example, your father who taught you to work hard or your mother who nurtured you so you wouldn't be a school shooter performed a service that provided all of the value of your entire life, and they got paid (or paid, if you turned out to be fucking worthless) nothing.

any easy ways to get real access to journals?
some public libraries also have access, for example

how else

>>16725023
Walk into a college and pay a student ten bucks to use their login for a few hours.

why are opensource fem solutions either complicated or complete dogshit? I wanted to recreate a work my prof did and wasted two fucking days playing around only to conclude that freetools cannot compete. All the free simulation tools seem to target a certain niche and its never aligned with your research...

Is science even worth it nowadays? Should I just join the trades? A robot's just going to be able to take water samples or mix chemicals in a few years anyway.

What are some mindblowing books on biology? I want books with math in them. Tell me of biology books.

>>16725054
discovery and optimization preceeds automation and manufacture, robots may do undergrad level work, but even in worse case scenario, quality control and setting will be done by humans, less educated you are, more likely you are to be replaced, blue collar trade jobs are being automated for decades and that trend will continue

There exists the ability to recall sound and create music inside of the mind, some people can imagine an apple inside of the mind, yet is there a group of people who can pontificate the odoriferous emanations within the mind space?
That is, ergo, vis a vis, can they create scent and smell, imagine smells, within the mind?
And are some smells and scents stronger and thicker and larger to imagine than others?

Can someone explain to me how I figure out, on the fly, how to decide how many digits to round to if not explicitly explained in the assignment?
My professor mentioned significant figures and while I know how to count significant figures that doesn't tell me if I should round to the hundredths or the thousands or what.

>>16725108
Yeah but a robot that can maneuver around unfinished without falling is more expensive than paying death benefits, workers' comp, and wages to a worker.

>>16725194
If it's not specific in the question it doesn't matter.

>>16725194
now here i may give a dumb answer, but if question mentions what youre measuring, you need to think about it, if your figures involve tons or hectolitres, if your answer includes every gram or mililiter, you may be giving values so specific that they are redundant, but than again, it really, really depends on the assignment

Okay, so I know mass and weight are different things and metric is king, blah blah blah, but since most normies aren't going to say 'my weight is 9.8*x(prefered unit)' and 'my mass is x(preferred unit)', can we just accept that arguing about mass and weight with normies is stupid and it just turns people off?
Like normies aren't talking about your weight on the moon, ever.

>>16724976
because society doesn't value value to society.

>>16725264
Society values value to society but if the guy who invented epipens asked to be paid their worth as a value to society we'd still be printing money to catch up.

Taking science classes with lab components online is a mistake. That is all.

I have a question about spectrometers. Always been around them at work (industrial fluid processing, automated stuff, piping networks, etc...) in the lab environment, mostly. Occasionally, there would be something like an in-process spectrometer for essentially checking that a pre-dyed ingredient was added to the correct amount in a flow/batch process.

My thought here is this-

What would be the useful accuracy of a benchtop liquid flow-through spectrometer with an 8-solenoid valve manifold for the input and an 8-solenoid valve manifold for the output. Have a recirc pump there in the loop with a quartz tube as the optical element along with all the attendant diffraction gratings, mirrors, lenses, etc...

I've read a few papers where a fiber optic strand is used as a contact probe into the solution under test, sometimes with a corner retroreflector inside.

My application is for measuring the specific mineral and fertilizer concentrations for a vertical gardening/nutrient film outdoor container garden. My concern is that the setup just will not give the type of accuracy I need to measure things like potassium to the +-10ppm level, alongside other spectrographically significant signatures that can be read on backend software.

I know of extremely expensive setups which can do this, but it is even remotely approachable at the $1,000 price point? It seems like it would be a very valuable tool in tracking and operation of a container garden, alongside the plots of rain, temperature, etc...

>>16724182 (OP)
Is it strictly coincidental that Oumuamua and 3I ATLAS came in at nearly the exact same x and y axis, as they passed the orbit of Jupiter?

Anyone else notice that one funny little detail?
Oumuamua fast, sharp Z axis entry from state of rest zone.
3I ATLAS following just a few years later, but specifically coming in at an angle near our solar plane, and obscured by the dense are behind it, as viewed by Earth.

Guys I'm not going to lie, it really looks like we just got scouted(Oumuamua), and now they are sending the bigger thing in(3I ATLAS).

Game theory it up, but that's what we have going on.
Small fast thing from zone of rest, scouts, leaves fast.
Bigger thing coming in, similar trajectory at Jupiter orbit, but doing its best to come in stealthy from the dense zone of the Milky Way behind it, from Earth observation angles.

Mr. Star, I don't feel so good.

I like to calculate tips in my head when I run. It’s easy and occupies my mind. I just move the decimal to the left and double the result.

Are there any other cool little math tricks I could do in my head when I run?

t. mathlet

>>16725054
Who decides what the robots should do?

>>16725194
Whether adding or multiplying, the answer has as many SF as the involved term with the fewest.

>>16725572
The person in charge of the operation, who is probably either a government bureaucrat or a MBA holding business guy.

Why does a L1 penalty term actually promote sparsity?
And please don't give me that bullshit geometric explanation.

>>16726067
When you are minimizing with a quadratic loss, there is not much benefit setting a coefficient to zero because due to the quadratic term the decrease in loss gets smaller and smaller as the coefficient gets small. With l1 loss, the decrease is linear and so, even as the coefficient gets small, it remains just as valuable to decrease the coefficient size.

>>16726095
Thanks, but that only explains why L2 does not help with sparsity.
I still need a good reason why L1 improves it.
I have a feeling it has something to do with it's subgradient and how you calculate with it, but I don't have any good sources for this theory.

Education is /sci/, right?
So I read in "Misfile" webcomic that girls are discriminated against in a math class by math teachers. I immediately thought it was unrealistic bullshit and dropped the comic.
But now that I think about it, maybe it's an American thing?.. In my country all math teachers are always female. Boys are known as hooligans by teachers, and girls are often teacher's pets, math included.
So, if you life in America, how true it is?

>>16726105
Well l1 penalty is not special in that sense, the same logic applies to sub-linear penalties as well, e.g. using |x|^p for 0 I do think the geometric picture helps actually as to why l1 penalty promotes sparsity. In picrel you can see the l1 ball slopes down somewhat narrowly from its ridges. The unpenalized minimum location is most likely away from the l1 ball and when you introduce penalization and constrain the location to lie in or on the l1 ball, the minimum location will most likely be on the ridges of the ball. This is because the ball slopes down fast from its ridges so if you are going down from the ridge you are changing the coefficients drastically and will not end up at the constrained minimum most likely.

The subgradient has something to do with what I said already. The subgradient of absolute value is step function and so the subgradient is constant, until it flips sign. So you keep making the same steps in the negative direction of the subgradient, regardless of how big the coefficients are, unlike quadratic case where the gradient steps become smaller.

If a unit square is divided into seven regions each having equal area, what is the minimum total length of all the region borders within the square?

>>16726138
Thanks for your take on this, but I still feel like the geometric explanation is bullshit.

/r/ing a third anon to give his opinion on all this.

>>16725127
I can do all the things you're talking about. Phonographic memory and auditory imagination, check. Apples and other objects, check.
Scent? Very easily, though intensity is a bit dulled, I can imagine some bad smells but it's harder to remember just how bad they were.
Is this really an uncommon trait? I thought memory and imagination were generic and happened on the qualia level.

>>16726107
Obviously there's a lot of room for variance, but overall such a scenario doesn't seem unrealistic. There's something of a stereotype that females are worse at mathematics than males (even though more and more studies are showing less and less of a gap). Could definitely see someone with that at the back of their mind giving preferential treatment to male students.
It doesn't have to be actively antagonistic to be discrimination, either. I've heard about teachers who will give a struggling male an actual explanation while the struggling female only gets "reassurance" that it's a difficult subject and that it's okay for them to find it hard

>>16726158
What's your issue with a ("the") geometric explanation?
An L1 ball has few extreme points, and each one of them is a "sparse point".

>>16726592
Mostly because my instincts are telling my it is nonsense.
Why would the solution always be conveniently located somewhere close to an axis?

>>16726896
>always
That's not the case. If you add a regularizing term [math]\alpha |x|[/math] then for sufficiently small values of [math]\alpha[/math] your solution won't be sparse. As you regularize more (increase [math]\alpha[/math]) the [math]x_j[/math]s one by one become zero.

>>16726896
The contours of the objective function are more likely to hit a corner point or ridge of the diamond shape, which will result in both cases in some coefficients being zero, than they are to hit a point of a sphere where there is sparsity. Picrel shows this for the corners, but for the ridges it helps to think in 3d. In 2d only the corner points set coefficients to zero, in 3d the ridges do so as well.
Think of it as the unconstrained minimum location pulling the coefficients to them, while the penalization is pulling the coefficients back to the l1 ball. With the geometric picture in mind, you can see why the constrained solution is more likely to lie on a corner or ridge and these points induce sparsity.

>>16726941
>in 3d the ridges do so as well
Ah, shit, I see it now. Thanks.
I think all those bad explanations I read in some papers kinda prevented me from seeing it.

And >>16726138 were right as well. Thank you, too.

>>16724182 (OP)
is this better than r/Scholar or whatever?
https://sci-net.xyz/

So I got a physics book.
What's a good place to actually...well, figure out how to apply what's written? I'm in a class but sometimes I feel like the book says XYZ and the online thingie asks for ABCKL

>>16727919
Have you considered the exercises written in the book?

>>16727953
No.

>>16726107
It used to be the case in America that girls were not expected to have a career in which they would need math more complicated than arithmetic, so if a girl was not doing well in trigonometry then there wasn't a compelling reason to spend effort teaching her, and if she went to university then it wasn't going to be for something in which calculus was necessary
The mathematics that women needed to be teachers was taught at the teacher's college and the more important quality was to be able to control the classroom
As a child grew older, more of their teachers would be men and these men had better educations than the female teachers
It's not so prevalent now, girls are overrepresented in universities in America (except for a few fields in which strong mathematical foundations are necessary)
Even the mathematics departments in universities have lots of female students because they were encouraged by their teachers growing up, and this portion will probably increase with time as the residual attitude of the last centuries goes away (ideas last longer than people do)
My recollection of university was that the math department had more female students than the computer science department, but whenever I see pictures of national delegations to international math competitions, the teams are entirely or mostly male, so maybe at the very top level of human ability (far above what I could ever achieve) there are sex-determined differences in mathematical ability
>>16725052
Particularly for software with narrow user bases, somebody has to either get paid to care about it, or otherwise benefit from the time they spend making and maintaining it-- probably your software was extensively cared for for four years while some guy was getting a PhD off of it but when he graduated he had more profitable things to do
>>16726150
Can you provide some more constraints? Because otherwise I can just plop in a Koch star as one of the regions and then the border length is infinite

So I'm lost in the woods here.
I was trying to be a good lad and calculate friction into downward acceleration on a ramp because we're learning friction this week. I'm either overthinking it, retarded, or both.
My variables:
The angle is a downward ramp that does down at 9 degrees.
Gravity is positive since we want to go down the ramp.
The kinetic friction coefficient is 0.3.
So, unless I'm pants on head:
a = 9.8(sin(9) - 0.3*cosine(9))
a ends up being a negative value, which since we're going downward isn't right.
Am I stupid? Because smooth steel balls don't fail to roll down wooden ramps, and they certainly don't roll upward on their own.

>>16724182 (OP)
Is mensa norway accurate? I got 120 on it

>>16728742
Is mensa really something you want to impress? Also, while Norway is a civilized nation, does anyone care about it outside of Norway?

>>16728742
No online iq test is accurate.

/med/ anons this is not a call for a diagnosis or any severe medical condition just some curious feature I noticed.

I get these odd spots sometimes,
Just behind the ear there's like a bone ridge, about 1cm after this ridge I have a semi paifull spot/zit, but currently in the exact same place behind both ears.
Just wondered if there was any plausile explanation for the placement like some lymph node or somethiing since they seem to reoccur at the same point?

>>16728863
Have you had this before? How often?

>>16728901
every couple of months usually I don't really pay attention anymore only this time they're both on roughly the same spot but either side of my head.

>>16728915
Have you reported this to a doctor before?
Are you too poor to just go to your annual wellness visit and point it out? I mean, if it's not a serious medical condition, your doc gets literal free money from the insurance company to prod you once a year.

So, I think I'm starting to get significant figures, but I'm not sure I understand why you use them. Even if, for example, I have a scale that only records to xxxx.y, if I can retrieve more accurate results for other parts of the equation I don't see any reason I should make the final answer more inaccurate just because my scale is a piece of shit.

I just need to complain. Why do we keep using greek letters instead of writing out what we mean? It's not like ink is a rare commodity now, and for digital print media you literally lose nothing by adding more pages.

>>16729487
Why is any notation invented? To make it easier to read and understand concepts. Any non-trivial statement becomes extremely long when we write it out in words.
Similarly, why do programmers not write in binary? Why add language and notation on top of it when storage space is rarely a limiting factor of the length of a program?

>>16728974
No not really, the spots seem to come and go I think my diet affects them.
they aren't pussy but more a painful raising.

Sex with Gaussian integral

>>16725025
>>16725023

Or install a keylogger at your local university's computer room, that's what i did

What would happen if there was a huge chuck, maybe a few kilograms of a radioactive metal like astatine, having half life of eight hours? Would it glow red hot from the radiation, or would it explode, etc? And what would be the ramifications of that much radiation released?

>>16729592
I mean, do universities even have computer rooms any more? I thought they just raised tuition by x and sold laptops for x-y in most cases now.

>>16729593
Well it would throw out a *lot* of alpha radiation which would be harmful at best, deadly at worst depending on proximity. It would not explode, radioactive decay never does. Heat would be generated simply due to the kinetic energy of the alpha particles interacting with the material but probably not enough to glow. After a day or two you would simply be left with a lump of lead or bismuth depending on the exact decay chain.

>>16729615
>I mean, do universities even have computer rooms any more?
Yes.

Is there software to bypass patreon avaliable?

>>16729965
You have no idea how websites work do you.

>>16729667
>Well it would throw out a *lot* of alpha radiation which would be harmful at best, deadly at worst depending on proximity
brainlet moment
external alpha radiation is harmless, it doesn't penetrate the skin

>>16729965
not for free

>>16730079
In general that is true but in high enough doses it is strongly ionizing and can still externally cause damage to someone's chromosomes.

Hi, whats the formula to calculate the velocity of an electron in a homemade electron accelerator using a power source of 20kv and a vacumm of 1399.881 pascals

>>16725448
It'll be like 75000 years until these objects go to other solar systems, relax

>>16730067
How?

>>16730192
All the logic and software that controls who can access what is stored on their servers. There is nothing you can install to bypass that.

So use someone else's credentials or actually pay people for their work.

>>16730216
Shut your ass up, nigga.


I ain't paying anything.

>>16730255
https://github.com/pkkyrtw4346273/UPDATED/blob/main/Patreon%20Viewer%20Tool%20to%20see%20Patreon%20content%20for%20free%20without%20a%20subscription.md

Saw this before, not sure if it works.

What is the scientific name of this creature?

What percentages of the coastline of the Caspian Sea do Kazakhstan, Russia, Azerbaijan, Iran, and Turkmenistan have?

Please answer in a pie chart
(1) which is labeled with the percentages and countries,
(2) which is in geographical order (like a map),
(3) in which Iran is at the bottom (just like on a map), and
(4) which I can download.

>>16730863
The Caspian Sea is bordered by five countries: Kazakhstan, Russia, Azerbaijan, Iran, and Turkmenistan. Based on available data, the approximate coastline lengths and their corresponding percentages are as follows:

Kazakhstan: 2,320 km, approximately 32.3%
Turkmenistan: 1,768 km, approximately 24.6%
Russia: 1,355 km, approximately 18.9%
Azerbaijan: 820 km, approximately 11.4%
Iran: 728 km, approximately 10.1%

These percentages are calculated from a total coastline length of approximately 7,000 km, as cited in some sources, though estimates vary slightly (e.g., 5,970 km in another source). The percentages are derived by dividing each country's coastline length by the total and multiplying by 100.

Below is a pie chart representing these percentages, arranged in geographical order with Iran at the bottom, as requested. The chart is labeled with countries and their respective percentages. You can download the chart by right-clicking on it in the interface where it is displayed or by using the download functionality provided by the platform.

Grok can make mistakes. Always check original sources.
Download

Explanation:
Labeled with Percentages and Countries: The chart labels each segment with the country name and its percentage (e.g., "Iran (10.1%)").
Geographical Order: The countries are arranged in a geographical sequence, starting with Iran at the bottom (south), followed by Azerbaijan (southwest), Russia (northwest), Kazakhstan (northeast), and Turkmenistan (southeast).
Iran at the Bottom: The rotation option is set to -162 degrees to position Iran at the bottom of the pie chart, aligning with its geographical position on a map.
Downloadable: The chart can be downloaded via the platform's interface (e.g., right-click or export options, depending on the system).

>>16730863
Did you make that chart? Cool

>>16726941
>[[[cost]]] function
its a function, there is nothing special about it
it doesnt deserve any adjective

>>16730998
This is what you nitpick? Boohoo, in the context of regularized regression, where there is a cost function and a penalization term, the pic called it a cost function.
Was it absolutely necessary to call it that? No.
Does it matter at all? Not even in the slightest.

>>16730905
>Did you make that chart?
grok.com made it

there are a lot of insults on 4chan.org
but grok.com never insults its users

and grok.com pays attention to every word in the user's input or prompt

and grok.com often gives detailed answers

but one of the bad things about grok.com is that it only gives "politically correct" answers
i always want read the most politically incorrect answers
in other words, grok.com spews propaganda
there's also a lot of propaganda on 4chan.org

what should i be doing outside of reading textbooks and doing the practice problems in them to learn math well?

Good free sources of information for learning about physics and engineering? I already know about openstax.
>>16731312
Finding a practical math application to your own life.

Not sure if I should ask /diy/ or you guys but here goes:

My shower drain was draining very slowly so I poured some limescale remover down it, then when I came back like 2 hours later my bathroom REEKED of sulfur, like Satan had eaten a thousand boiled eggs in it, what does this mean?

What causes mercury to be the least heat conductive metal?

>>16733018
Same reason it's a liquid at room temperature. Weak bonding between the atoms.

>>16730863
Nice chart

>>16730863
>>16730877
Look up the coastline paradox and you'll understand why the coastline measurement varies.

>>16733110
>the coastline paradox
I read the first 4 paragraphs of the following website.
https://en.wikipedia.org/wiki/Coastline_paradox

Why can light pass through carbon when it is in the diamond form but not when it's in the ugly coal form?

>>16733364
Coal isn't pure carbon, coal is a disordered heterogeneous compound which either scatters or absorbs visible light. While diamond is a a single ordered crystalline lattice of only carbon which happens to be mostly transparent to visible light.

Why can't the heat energy in your house be taken and used to power a fan? That way not only would you get free energy to power the fan, the house would also get cooler as the thermal energy is estracted from the air. So it would be a double-win situation. Why can we not do this?

Why can't the heat energy in your house be taken and used to power a fan? That way not only would you get free energy to power the fan, the house would also get cooler as the thermal energy is extracted from the air. So it would be a double-win situation. Why is there no such an invention?

>>16733596
Basic thermodynamics. To do work with heat (e.g. generate electricity) requires a temperature differential (something has to be hot, something else has to be cold). Just having a warm house doesn't fit that requirement.

>>16733337

But how does this curve behave in the vicinity of Bournemouth? There, I believe, the riddle may be solved. And I propose that to calculate this, the information should be given to a new computer, also called Bournemouth.

i'm just getting completely filtered by powers of i in the denominator. how does this shit work?

>>16733862
Just keep removing powers of 4:

[math]i^{11} = i^{4} \cdot i^{4} \cdot i^3 = (1) \cdot (1) \cdot i^3 = -i[/math], and by the same logic [math]i^{21} = i[/math]

>>16733877
i get that part, it's the [math]\frac 1{-i}=i[/math] part that i'm struggling to comprehend

>>16733878
actually, is that part i'm misinterpreting that i should be flipping the sign like a complex number when i multiply it across the numerator and denominator?
[math]0-i [/math]becomes [math]0+i[/math]?

>>16733878
[math]\frac{1}{-i}=\frac{i^4}{i^3}=i^(4-3)=i^1=i[/math]

>>16733894
mind blown

Does relativistic mass actually affect gravity? Imagine you had a hypothetical super accurate scale and you weighed a marble. Then you weigh the marble again except this time it's rolling on the scale meaning that it has gained a tiny bit of relativistic mass on top of its original rest mass. Would the marble weigh more now?

>>16734270
> Does relativistic mass actually affect gravity?
Yes. In General Relativity all forms of mass-energy affect the curvature of spacetime so a moving object would generate more gravity. In our everyday experience though the effect would be so small as to be impossible to measure.

> Would the marble weigh more now?
That is actually a hard question to answer. It depends on exactly what you mean by 'weigh', the difference between rest mass and inertial mass and gravitational mass, how you would perform such a measurement, etc. The simple answer however would be no, the rest mass never changes so it would 'weigh' the same.

>>16733878
>>16733894
Or alternatively:

[math]\frac{1}{-i} =\frac{1}{-i}\cdot\frac{i}{i} = \frac{i}{-i^2} = \frac{i}{1} = i[/math]

>>16734313
But if it's rolling on the scale, it's not at rest hence has more than rest mass. Or you could have flywheel on the scale and spin it very fast, similarly its mass should increase by tiny bit.

>>16734374
It is not that simple. From the reference frame of the marble it is not moving so it only has its rest mass.

anons, i have used an aluminum L-shaped plate as means of attaching a contraption, that is going to endure repeated pressure
i got curious if it was the right decision and googled "whats more flexible steel or aluminium?"
there seem to be conflicting answers, or im just not familiar with some of the terms used in the articles
is there anyone who can answer it with certainty? I have access to random metal scraps, and can probably find a steel "L"-shaped plate, but dont to waste time if aluminium is better. Its a 4mm plate, if it matters. Im looking for the most rigid material, that rather snaps than flexes ( within reason )

tl;dr
whats is more rigid, less bound to flexing under pressure - aluminium or steel?

>>16734374
>>16734313
Mass is a measure of inertia.

>>16734527
Your biggest concern here may need to be fracturing. Aluminum WILL eventually crack if it is repeatedly flexed. It is only a matter of time depending on thickness.
Steel and titanium are fairly unique in that they don't do this if you don't flex them too severely.
That being said, just use a thicker piece of aluminum.
As to which one is bendier, all else being equal, you want to use the shear modulus for an L-shape. Steel is, as your intuition probably told you, far less flexible.
We use steel for springs because of the repeat-flex-fracture problem, not because it's easier to bend.

>>16724182 (OP)
how do i convince my doctor to run tests for bile reflux not just acid reflux?

>>16734692
>how do i convince my doctor to run tests for bile reflux not just acid reflux?
Ask him. Hospitals love money. They'll happily charge you for another test.
Or do you live in one of those countries where you have to wait in line for seven hours to get medical treatment because it's "free"?

>>16734692
The real trick is convincing insurance that it's necessary if you're in America.

On Friday 25 July, I went to [...], and bought a package containing three paprikas. The green paprika had 2 lobes, the yellow paprika had 3 lobes, and the red paprika had 4 lobes.

What's the probability of getting three distinctly-lobed paprikas in one package?

It might be 6*p*q*r, where:
o = prob(1 lobe) = 0
p = prob(2 lobes)
q = prob(3 lobes)
r = prob(4 lobes)
s = prob(5 lobes) = 0
t = prob(6 lobes) = 0
...

Any good way to get into organic/biochemistry with a high school understanding of chemistry in general? The entire thing's fascinating but youtube video series are just dry as shit

>>16734656
thank you for taking time to answer, anon!
i guess i will keep the aluminium, since i have already spent some time on it
but i will look for a steel alternative, just to have something laying around in case i need it

How can I go from [math]\eta_{\mu\nu} = {\Lambda^\rho}_\mu{\Lambda^\sigma}_\nu\eta_{\rho\sigma}[/math] to [math]\eta = \Lambda^T\eta\Lambda[/math]? Here [math]\eta[/math] represents the metric and [math]\Lambda[/math] is orthogonal.

how long is it supposed to take me to learn math? im going over a pre-calc book and i get stuck on 1 topic for atleast a couple days before i feel comfortable moving on.

>>16735056
>how long is it supposed to take me to learn math? im going over a pre-calc book and i get stuck on 1 topic for atleast a couple days before i feel comfortable moving on.
Look at EXAMPLE PROBLEMS. If you try to dwell on their textbook explanations, you will lose your mind.
That feeling of not being ready before they push you onto the next topic...that's totally normal. We all experience that. You get used to it.
Miserable, isn't it.

>>16735028
You'll need a Christoffel Symbol for that jump.

if you're working through a math textbook and you find another one on the same subject you think you would like better how would you decide whether to switch or not? I don't want to become a textbook hopper who doesn't learn shit but I might learn better with the other one.

>>16734899
(p + q + r)^3 = [image]

>>16734720
you'd be shocked how long i've been terribly sick and doctors just tell me to live with it. it took 4 years of living with horrible sciatica for them to send me to physical therapy. i don't know if it's just cause i look a certain way and they think "well he can handle it" or what. i have to sleep elevated every night and no antacid helps not even the new experimental ones and not even if i just don't eat anything for 10 hours before bed. i'm convinced it's bile coming up into my stomach and throat making me sick when i lay down.

Hey medfags what do
I've been getting chronic stomach pain ever since I've been taking ADHD meds ~2 months ago, my psychiatrist switched me from adderall to ritalin and the pain still occurs but the medication is flawless in ever other way so I don't want to switch. I'm also an insomniac and been taking zzquill for the past ~3 years.

So I finally decided to go to college after 2 bad years. I'll be 21 in a few months. I'll be majoring in Mathematics, but I'm supposed to take courses in Physics, Biochemistry, Environmental Sciences, Psychology, and more bloat. It's been 3 years since I concerned myself with Chemistry and I've never studied Organic Chemistry. I asked a friend and he said you're supposed to know organic chemistry beforehand. So anons how do I cope? I've never been good at chemistry and always thought maybe it's a pedagogical issue not a subject one.

>>16736394
You cope by educating yourself. That's what the general courses are meant to do, give you a well-rounded education. There will often be times in life you have to do things you don't want to, this is just the first of many.

>>16736514
>t. educated idiot
Autodidactic != a degree

I just had an epiphany about the incredibly overlap between quantum physics and relativity and Eastern Philosophy. I then learned that many of the great physicists of the 20th century (Oppenheimer, Bohr, Schrödinger, and more) were deep into Buddhist thought and other Eastern approaches to metaphysics.
Am I late to the party?

>>16737831
Yes. Students of the era (remember that universities of the period was all extremely upper class) were taught the 'classical education' including the religions of other cultures.

[analysis] I finally understand the logic and rationale behind a basic delta-epsilon proof. Now I tried to prove that Lim x^3 as x approaches 1 = 1. I've never studied anything beyond linear function proofs, just felt like going for something different. How reasonable is my approach to the cubic function? Note this isn't a formal proof attempt, so please don't focus on the sloppiness

Just putting this out there to give anons a little more ammunition for the next time someone shills a lex thread on here
https://www.youtube.com/watch?v=Z1Ua1hVRtdE

If E=mc^2, what is the total energy of the universe? I thought Feynman said there is enough energy in an empty cubic meter of space to boil all the oceans on Earth. So, what is the total energy, and where does it come from? Since it takes so much energy to create matter, is the big bang just excess energy converted to matter to maintain the energy balance?

>>16738739
> what is the total energy of the universe?
Adding up all the matter, dark matter and dark energy of the observable universe gives and answer of roughly [math]10^{70}[/math] joules.
> Feynman said there is enough energy in an empty cubic meter of space to boil all the oceans on Earth
This isn't strictly true since the average density of empty space is about 6 hydrogen atoms per cubic meter. iirc what he was describing - in a pop-science manner - was zero point energy and how empty space isn't truly empty. Since that energy is impossible to extract it can't be used to boil any oceans I'm afraid.
> what is the total energy
Since we don't know the total size of the universe, or if it's finite or infinite, there is no answer to that.
> is the big bang just excess energy converted to matter
Yes, all the matter in the universe comes from the initial energy of the big bang.
> and where does it come from
We don't know, it may even be a nonsensical question. There is one idea that Hawking suggested that the positive mass-energy density of the big bang is balanced by the negative energy density of the gravity it produces so the combined total energy of the universe is zero.

>>16738739
The original version is E=3/8MC^2 and was written by Fritz Hasenohrl.

Einstein Never ever wrote E=MC^2

The universe, under certain situations, will withdraw or deposit energy directly from the fabric of space.

>>16738766
Dark Matter and Dark Energy are names for bad math and handwaving in a failed attempt at pretending Standard Model is a unified theory--which it isn't.

The big bang is still a theory and scientists have a habit of ignoring all the counter evidence to it while paradoxically pretending Standard Model physics is sufficient to explain the observable universe.

>>16737831
>>16737856
They also learned projective geometry.

>>16738481
You seem to be on the right track. Some thoughts:
Your [math]\exists[/math] is mirrored.
It's not true that [math]x^2 \geq x[/math] for each [math]x \in \mathbb R[/math] (but you don't really need this either).
I think the important thing you notice at the end is that continuity is a local property, so you can choose your [math]\delta[/math] (not [math]\varepsilon[/math]!) taking into account how large you expect [math]x^2+x+1[/math] to be.

>>16738912
*yawn* gbt /x/ schizo

Three uniformly random points are chosen inside of a circle. Those three points determine the locations of the three legs (with equal length) under a circular tabletop which is being built.

What is the probability that the table does not fall over and that no leg supports more than 50% of the table's weight?

>>16724182 (OP)
Is there a way to get acs in focus journals torrent etc.

How can I paste polygon data into the following website?www.desmos.com/calculator
I really want to know, because I want to graph eight polygons in one file.

I'm an online student. What's a good self-study method? Fifteen minute bursts? One hour per day?

>>16724182 (OP)
You can post code blocks on the dra/g/on maid board like this
[code]
Code goes here....
[/code]
Is there anything like this on /sci/?

>>16740025
[math]\texttt{There's this: \\texttt\{text goes here\} in [math] blocks. Not quite code formatting but a monospace font at least.}[/math]

>>16740053
Thank you for telling me. I will try this.
[eqn]
\texttt{code goes here...}

Multiline?
[/eqn]
Will I get banned for maidposting here? I finished my programming language and I want to publish it, but the dra/g/on maid board jannies give me an unappealable three day all boards ban on sight. I also finished my Bipolar Binary Neural Network counter and I want to publish it here as well.

>>16740071
[eqn]
\texttt{line1\\line2?}
[/eqn]

How do I find multiples of 2 numbers with specific patterns of digits in specific columns?

Say for example, I want to find multiples of 33 and 567 that end in ***567. I only care about the digits in the ones, tens, and hundreds place in this example.
How would I go about finding that? Is there a specific term for this?


dont have a good pic for this.

>>16740076
In general, for whatever columns you want? You can't. But if you mean columns up to a specific point, then modular arithmetic is your friend.

>>16740171
It appears that this works?
>>16740147

>>16740171
yeah i was just looking for columns up to a specific point.

Though a maid poster gave an answer here: >>16740029

Hello, anons. Would someone be able to provide more insight? I noticed that I am disadvantaged in pure numerical analysis. I don't understand how to find patterns for sequences and series. If you were to give me a list of numbers and ask me to formulate an equation, a series that connects them, I would have a difficult time, regardless of how simple it is. However, I am better at spatial math; I can understand the problem significantly better if I look at it from a geometrical sense. I am anxious that this will make me a terrible engineer and coder; coding relies heavily on logical thinking. Would it be possible to improve?

>>16740270
Are you trying to become an academic coder, or a wagie? If you are trying to become a wagie, you will never ever need math and you should be more focused on being able to read framework documentation and apply the frameworks. You should also get comfortable with babysitting LLMs. Wagies don't actually do computer science or math. Learning AWS will get you further than anything related to a sequence or series or even logic.

>>16740276
I am majoring in electrical engineering with a goal in robotics. Nothing academic, but I feel like this will require a smidge of rigorous math combined with software. So far, none of my math classes feel impossible or too harsh.

>>16740283
There is a good chance your actual workflow will mostly be using dependencies and APIs written by someone else, so again you're probably looking more at reading and understanding documentation than advanced math. Most modern coding is basically just stitching together different dependencies. Python is particularly notorious for this for example. That language is almost just a wrapper for gluing dependencies written in C together. If you are playing with C directly, there is still a good chance you will primarily be using libraries written by other people and will not actually need advanced math. Programming is way easier than most people imagine.

Can someone give me an intuitive explanation of why the power rule in integration/differentiation works?
These are obvious:
>f(x)=x when f'(x)=1
>f(x)=(x^2)/2 when f'(x)=x
I brute forced this one as a limit of a harmonic sum:
>f(x)=(x^3)/3 when f'(x)=x^2

But is there some retard simple way to prove the generalization?:
>f(x)=(x^(n+1))/(n+1) when f'(x)=x^n

>>16740285
Thanks, anon. I'll continue to work on my math, but I'll focus more on my practical skills then.

Why can't we eat meat raw if we evolved to eat meat

>>16740372
Raw meat is fine. It's whatever it may be contaminated with that might cause issues.
If the animal was healthy before butchering and the meat was handled in a sanitary way then there's nothing wrong with eating it.

>>16740289
You can just use induction to prove it for differentiation, integration is simply the reverse operation.

The base case is trivial: [math]\frac{d}{dx} x = 1[/math]. So assuming that [math]\frac{d}{dx} x^{n} = nx^{n-1}[/math] is true, then all that is left is to prove that [math]\frac{d}{dx} x^{n+1} = (n+1)x^{n}[/math].

You can do this using the product rule:

[math]\frac{d}{dx} x^{n+1} = \frac{d}{dx} (x^{n} \cdot x) = x \frac{d}{dx} (x^{n}) + x^{n} \frac{d}{dx} (x) = x(nx^{n-1}) + x^{n} = nx^{n} + x^{n} = (n+1)x^{n}[/math]

>>16725078
HC Berg random walks in biology.
>>16739226
It converges pretty slowly to around 12%. I might see if Maxima can solve it as a 5 dimensional integral, but randomly legged tables or quant math in general are relatively low on my list of things to practice.

What would happen is a grain of rice was moving so fast that its kinetic energy would be equal to a nuclear bomb? Would it just pass through anything it touches like a lazer and shoot into space or would it make a massive explosion and destruction?

>>16740917
>massive explosion and destruction
That one.
Ignoring relativistic effects:
>grain makes impact
>attempts to push material aside so it can pass through
>material impacts more material at high speed
>shockwave disperses through impacted object
>object and rice obliterated in massive explosion

Relativistic effects accounted for, the rice would just explode due to Unruh radiation before impacting anything.

i'm not able to wrap my head around the process of getting (x-a)(x+a-2)
when i try factoring, i get to x(x-2)-a(a-2)
but how does (x-2) and (a-2) combine into (x+a-2)

>>16741100
it might not be immediately obvious if you don't know what to look for, but a very useful thing to keep in mind is that
[math]x^2-a^2=(x-a) (x+a)[/math]
so [math]x^2-a^2-2x+2a = (x-a) (x+a) - 2 (x-a)[/math]

>>16741100
Honestly man, if you're in school and you see a question like this, where you see a smaller degree polynomial at the bottom and a larger degree polynomial on top, your intuition should just be to check if any factors of the denominator are a factor of the numerator. While tricks like what this guy >>16741109 said aren't bad at all, it's such a rare ass thing that in general just do simple long division. Takes like < 15 seconds to figure out it's a factor.

If you really want to know how to start from the obvious x(x-2)-a(a-2), then a good trick you really should know is to add and subtract the same number, so adding 0 = ax - ax. Adding the right 0 or multiplying the right 1 is good.
>x(x-2)-a(a-2) = x(x-2) + ax - a(a-2) - ax = x(x - 2 + a) - a(a - 2 + x)

>>16741141
like, the goal is to see if it's possible to make the (x-2) and (a-2) symmetric in some way so that you can factor out the (x-a) that you're guessing is possible to do, and ax = xa is a symmetric enough to do the job to prove your hunch correct.

>>16741141
like, the goal is to see if it's possible to "perturb" the (x-2) and (a-2) in some way [that doesn't break the rules, like adding 0 or multiplying by 1] so they become symmetric, meaning you can then factor out the (x-a) that you're guessing is possible to do, and ax = xa is a symmetric enough to do the job to prove your hunch correct.

>>16741144
Jesus, sorry, last fucking thing. You can figure out immediately that the monomial at the bottom is a factor of the top because plugging in "a" into the numerator polynomial obviously becomes 0. After this easy check, the next move would be to see if you can figure it out what it divides into quickly. In this case where you can't figure it out in like 10 seconds, then resort to long division.

if E=mc^2 what type of energy does is E represent? A combination of all the fields, one field? Is there a limit on energy density that if exceeded matter must be created?

The first four planets are rock/solid, but the sun is only gas, and the rest of the planets beyond Mars are gas? Why the rocks only exist at a specific distance from the sun to form solid planets but no solids in the sun?

If the same types of solids that make up Venus, Mercury, Earth, and Mars also exist in the sun, what is happening to those elements being trapped in fusion reactor (assuming the heavier elements have migrated to the core due to their density). Are heavy elements being created prior to supernova?

>>16741242
The original way the relationship was represented was m=E/(c^2).
The point that was being made was that mass is an emergent property of the energy in a system. So any intrinsic energy in a system IS mass.
>But what about massless particles?
They have no intrinsic energy. The energy of a photon is entirely dependent on your frame of reference ie. Doppler shift.

Okay, so a contravariant vector [math]\vec{v}=v^i e_i[/math] has contravariant components v^i.
Are the basis vectors e_i covariant, or is it just notation? The index is a subscript, it gets summed over with v^i. But a vector should surely be decomposed into other vectors, not covectors right?

Can knowledge be implanted? Maybe not subjective knowledge like recalling an event, but objective knowledge like a language

Hold on, if you could observe everything at once from the 4th dimension, doesn't that imply free will is fake and everything is predetermined?

>>16741265
In theory? Yes. The brain is a physical thing following the standard laws of physics and matter.
In practice? Probably not in this millennia.

We aren't close to understanding how memory is stored in the brain or even where. Is it purely chemical? Neural plasticity? How does short term memory move to long term memory? Fuck knows what else? Then even if we did know all the biochemical processes and brain structures involved we have no ideas what technology could then somehow then implant new knowledge into a living brain without fucking it all up.

>>16741246
> Why the rocks only exist at a specific distance from the sun to form solid planets but no solids in the sun?
The sun was originally formed from a cloud of dust (rock) and gases which heated up due to gravity (friction etc) and so were the planets. Any rocks (comets etc) that now fall into the Sun simply get vaporised and turned into a plasma of the individual nuclei. They will then be part of fusion processes and all the heavier elements will gravitate towards the core of the star.

As for why the inner planets are rocky, that is still being studied. We thought we knew a few decades ago, but given what we now know from observation of exo-planets and other solar systems it might just come down to luck. Or more precisely the initial conditions during the early formation of the star system. We've seen huge gas giants that can be close to stars, rocky ones far out.

>>16741288
I'm assuming you're describing "4D" as 3D space + time.
The answer depends entirely on your definition of "free will." As long as you agree that there is a "you" that is making decisions, then those decisions being plottable as a function only invalidates free will if your definition explicitly denies such a quality.

I need a particle physics book and a general medical book

>>16741294
>the heavier elements will gravitate towards the core of the star.
yes, and they are subjected to the neutrons from from the fusion process, so are these heavier elements being transformed into still heavier elements after millions of years? Or they remain unchanged and all the heavier elements are created as the fusion cycle moves up the element chain until it stops or supernova explosion to distribute them into space? Or, is the majority of the creations of the heave elements only during the supernova?

>>16742051
Towards the center of the star the core is formed of shells of the heavier elements, the heaviest from the fusion process being iron. Heavier elements than that are then formed during the supernova. They are also created from the collision of two neutron stars, in recent years there is some research suggesting that this is actually the primary method that heavy elements are formed. Either way, that means that any gold you see is the result of the death of one or more stars.

>>16742064
Thank you for your answer.
not trying to be difficult here, but trying to better explain my question - first generation of stars start with only hydrogen, then second and third generation star formation would have heavier elements from the initial material available the accretion disc (heavy elements created and blasted out from the explosion of first generation stars). Earth has lead, uranium, titanium, gold, silver etc. So I assume these elements are also found in the cores of Venus and Mercury, and I assume therefore these same elements are already in the core of the sun from the first formation of the solar system - so what are these heavier elements doing (what is happening to them) in the core of the sun during the early hydrogen burning process and before end of the hydrogen burning process, long before the process moves beyond helium. It seems these already existing heavier elements are in a fusion furnace for billions of years, or are they destroyed by constant flux of neutrons in the early life of the Sun?

>>16742105
You're correct. Later generation stars are more "metal" rich (astronomers call anything not Hydrogen or Helium a metal), and yes there will be some of those elements you mentioned in the Sun but the amounts are so insignificant compared to everything else they can just be ignored. If they do fuse to form super heavy elements they will be radioactively unstable and will not last for long reverting back to lighter elements, or as you say elements like Uranium are broken apart by neutron flux.

What is the largest known pair of twin primes?

Are there infinite different sets of prime numbers such that the average of prime numbers in the set is also a prime?

>>16742457
According to the wiki: [math]2996863034895 \times 2^{1290000} \pm 1[/math]
>>16742465
Since there are an infinite number of sets you could create that would seem plausible.

Scientifically speaking is this accurate?

>>16742871
Yes. Given the thermal expansion of iron and the height of the tower, a rough calculation does give a result close to that statement given a ~20 degree temperature change.

What happened to IMO site? This page was available 1 month ago, but now it's empty. Did it get hacked?

https://www.imo-official.org/year_individual_r.aspx?year=2025

Store the data on github so the pages are reversible to an earlier commit if anything happened.

Studying Analysis II at the same time as Analysis I. Is it possible? I started an Analysis II course and an Analysis I course at the same time. I already did Complex Analysis last semester by the way, don't ask me why. Do you guys think this is feasible? The book being used is Tao.

how is the biotech industry doing? i heard that the cuts really hurt

t. senior

Thoughts on picrel?

>>16742031
>particle physics
Griffith

>>16744485
You can literally read (emphasis on read only) through Tao on a free weekend. It's not meant to be a hard book. Just read through #1, then reread+do problems on a schedule

why does the order of shifting or stretching first matter here?

>>16745643
Presumably to turn each function into f(x) ?

>>16745643
first is bx-h
second expands to bx-bh
the two are not the same and the order reflects that

>>16724182 (OP)
would it be possible for a qbit in a quantum computer somehow get entagled with a quantum particle in your brain?
is how often can a qbit entagle with more than one particle?could script kiidies somehow hack quantum computers to so such things?

are we going to run out of oil in 20 years?

>>16745673
No, there are still large deposits out there but they are currently prohibited by cost to extract - once oil prices increase they become economically viable. That also includes non-standard resources like bitumen sands that are extremely difficult to refine. So oil as a 'cheap' commodity may end, but we have some time yet before it completely vanishes.

>>16745671
Tl;dr: no. And it probably wouldn't matter if they did.
Particles don't spontaneously become entangled. The "spooky action at a distance" meme is mostly popsci slop.

Imagine putting two opposite shoes in different boxes and shuffling them. Now you don't know what shoe is in either box, but you do know that whatever's in one, the opposite is in the other. They remain in this state regardless of how far apart they are. The two shoes are "entangled" until one of the boxes gets ficked with in some way. The entanglement "collapses" because you can't be certain the contents can't be tampered with.

Now imagine a particle decays into two particles with opposite spin. You don't know which particle is which, but...
You get the idea.

>>16745699
so people really shoulnd't be worried about if any oil will be left but rather how expensive its going to become.

>>16745700
so does that mean "quantum mechanics" means that every quantum particle is just unique identity in context of the other. and this identity is its spin or something?

>>16745717
>>16745673
Yeah, I know people who work in oil and gas and according to them we've been "running out of oil" for the past 50 years. New innovations, stuff like shale and fracking, happen every few years that increase the supply that is viable to extract cheaply. Eventually though we will get to the point where it costs like $10,000 to extract a barrel of oil and we'll just switch to whatever else cuz it's cheaper. I personally think solar/nuclear will get extremely cheap even before we hit that point though so it may be a moot point.

>>16745723
like two best friends that have nicknames for each other but then drift apart for so long they wouls forget those nicknames.

what is the name of the type of rate for osrs xp again? (ammount req increases by 10% every level e.g. 100xp to hit lvl2, 11xp for lvl3 etc)

>>16746013
Let [math]a_n[/math] be the total exp needed until level [math]n[/math]. You're given

[eqn]a_{n+2} - a_{n+1} = 1.1 \cdot (a_{n+1} - a_n) \\
a_2 - a_1 = 100 \\
a_1 = 0[/eqn]

Solving this recurrence gives
[eqn]a_n = \frac{10000}{11} \left(\frac{11}{10} \right)^n - 1000 [/eqn]

How do you do effective research with PNC/Pubmed articles?
I got into it with someone and realized I don't know as much as I should about these, and I struggle to understand what the people writing the articles are trying to communicate.
I also don't know how to verify their claims. They were very insistent that these sources (and the peer-review process as a whole) are actually trustworthy and important to reference before making medical decisions.

Aside from checking accreditation, is there a way to find out if a college is a degree mill that isn't just googling is (blank) a degree mill or is (blank) academically rigorous?

>>16725453
You could move to Germany where 10% tips are usual. You would get way further in shorter time.
One of my favorite math tricks is squaring numbers that end in five: if you have a number of the form A5 (like 35, 145,...) you can easily square it by calculating A×(A+1) and attaching 25:
35 -> 3×4=12 -> 352=1225
145 -> 14×15=210 -> 21025
...
This is one of the math tricks I've used the most in my life.

>>16725383
Unsure if you're still watching this thread but I'd like to hear some more details about this. What is the solution under test, exactly? Why do you need inline measurement? And with all the other solution components, is spectrophotometry specific enough to potassium?

>>16729255
This is the whole point of significant figures doofus
Yes, the precision of the calculation is limited by the weakest link
Replace the scale by my aunt Sharon who just looks at the object from 5 m away and gives her guess
Do you not expect any loss of precision in calculations based on aunt Sharon compared to calculations based on the scale?

Approximately how many years away are we from fully functional complete uterus transplantation for males?

I'm asking because I don't believe in medical procedures that reduce the functionality of the body and that's what current M2F gender reassignment surgeries do, but with complete uterus transplantation functionality that is reproduction should/could be maintained.

Any online graphing calculators that have the option to to represent the imaginary number line as the "y-axis" like I did in high school exercises?
Like I want to be able to input e^(ix) and get a circle rather than an error.

>>16746694
Desmos

>>16746705
Wtf? Is there anywhere I could have gone to independently figure out t is the variable for complex functions in desmos? I tried looking up complex function examples for desmos and it gave me a bunch of bullshit tables/translations and shit.

(Yes, I know t takes the place of x when it's function over time).

Thank you very much regardless.

can you induce placebo symptoms on purpose without the use of a placebo? like through "pure willpower" or something like that since evidently your body is capable of creating the effect on its own

>>16747648
The whole point is you don't know it's placebo.
Prayer works if you believe it works.

>>16747648
Yeah you can try taking sugar pills
>>16747653
Placebo effect sometimes still works even if you know it's a placebo

How do I get better retention for definitions, theorems and the such? Going back to school and while I still get the big ideas from my main math courses I couldn't prove to you or even really state the big theorems in undergrad analysis or algebra anymore. Do you guys have to look them up again from time to time? Frustrating to have studied so hard and then forgotten everything

>>16747955
Practice and meditation.
This is gonna sound really autistic, because it is, but for a vaguely interesting proof I'll sometimes open MSPaint and use it as a whiteboard and draw out the proof as if I'm giving myself the lecture via internal monologue.

There's also the general effect that the more you understand the less you have to remember. Once you build the intuition, which still comes from practice and meditation, then it won't be so taxing on your memory.

>>16748059
That makes sense. How often do you do that? I took analysis and algebra back pre covid and am pushing to prepare myself for a graduate program now. Would you advise just going through the textbooks I used back then and doing a lot of problems?

I'd like to think I still have the intuition of the main ideas but I don't have the mastery you mention. Am I overestimating myself?

>>16748127
>Would you advise just going through the textbooks I used back then and doing a lot of problems?
Exactly. Math is like any other skill. Go through the steps enough times and you'll eventually get to a point where you forget why any of this was even difficult for you in the first place.

Whatever you like to tell yourself now, there was a time when simple "solve for x" style linear equations could trip you up sometimes.

>>16748142
Excuse you i'll have you know I still mess up basic addition at times

I sometimes mess up basic arithmetic in ways that are related but absurd. eg. seeing 4*2 and writing 16.

How low is my IQ and/or how over is it for me?

I have a friend with his degree in physics who says he doesn't believe in tensors. The fuck does that even mean?

How do I rearrange these equations to calculate N, A and S given L, D and C?
(I don't know basic basics about math)

I don't know shit about math.
I understand that 0.999 repeating is equal to 1, but I was wondering, is there an expression in math for infinitely many repeating 0's followed by a 1 at the "end?" A theoretical number which, added to 0.999 repeating, would turn it to an even 1?

>>16749346
Sort of.
Since [math]0.999...=1[/math], subtracting from both sides shows you that your "theoretical number" is just 0.
However, there are systems where this isn't true. You likely have at least some awareness of the concept of infinity - something is considered infinite if it's larger than any real number, to put it loosely. There's a mirror concept called an infinitesimal, [math]\epsilon[/math] which is something smaller than any positive real number but still larger than 0 - sort of a 1/infinity situation.
Most of the time infinitesimals turn up, they're shorthand for "it doesn't matter how small you set this; any positive real number works here". But there are some very nonstandard frameworks which consider infinitesimals to be actual numbers with well-defined values, rather than just "smaller than whatever you care about". And for some of those, yes, you can say that [math]0.999... + \epsilon = 1[/math], though by extension it's no longer true that [math]0.999...=1[/math] since [math]\epsilon \neq 0[/math]

>>16749307
>How do I rearrange these equations to calculate N, A and S given L, D and C?
It's a linear algebra problem, with trigonometric coefficients.
Solution instructions:
1:
Go to the following website.
www.wolframalpha.com
2:
Copy and paste the following expression into the "Enter [...]" field.
Solve[{L = N Cos[α] – A Sin[α], D = A Cos[α] Cos[ψ] – N Sin[α] Cos[ψ], C = S Cos[ψ] + A Cos[α] Sin[ψ] – N Sin[α] Sin[ψ]}, {N, A, S}]
3:
Click or tap on the white on orange "=" button.
The first five solutions or roots will be displayed.
4:
Click or tap on the blue on white "More roots" button to display the first ten solutions or roots.
5:
Click or tap on that button again to display all of the fifteen solutions or roots.

>>16749307
https://www.wolframalpha.com/input?i=Solve%5B%7BL+%3D+N+Cos%5B%CE%B1%5D+-+A+Sin%5B%CE%B1%5D%2C+D+%3D+A+Cos%5B%CE%B1%5D+Cos%5B%CF%88%5D+-+N+Sin%5B%CE%B1%5D+Cos%5B%CF%88%5D%2C+C+%3D+S+Cos%5B%CF%88%5D+%2B+A+Cos%5B%CE%B1%5D+Sin%5B%CF%88%5D+-+N+Sin%5B%CE%B1%5D+Sin%5B%CF%88%5D%7D%2C+%7BN%2C+A%2C+S%7D%5D

>>16749346
>infinitely many repeating 0's followed by a 1 at the "end["]
That's the smallest positive number.

>>16749603
>>16749607
Thank you but sorry I kind of worded my question badly, I didn't exactly mean rearrange as in rearranging, I meant it more like rotating the other way. The equations above are for rotating cartesian coordinates into different reference frames.
I know the equations in 2 dimensions are:
L = N * cos(alpha) - A * sin(alpha)
D = N * sin(alpha) + A * cos(alpha)
And then the other way around is:
N = L * cos(alpha) + D * sin(alpha)
A = -L * sin(alpha) + D * cos(alpha)
But I'm dealing with a 3rd dimension that uses an extra angle and axis which modifies the last two equations and I don't know how to change it to rotate it the other way around

Is there still research being made in Electromagnetism or is this field already “solved”? Is there anything left to discover in it? Do physicists these days only research Quantum Mechanics and its variants like Quantum Gravity and String Theory?

>>16724679
inadvisable.

>>16749932
Depends on what you mean by "solved". Do we have equations that fully describe the classical electromagnetic force? Yes. Do we then understand, can calculate, and predict everything that happens? No.

Mainly this situations that involve extremely highly magnetic fields such as fusion reactors, stellar magnetic fields, and quasars. We don't have computers powerful enough to "solve" those systems.

learning basics of sets and I'm stuck with this question.
"consider 3 sets A,B,C with A∩B⊆C and A∩B ! =O. Now if A−C⊆B then is A⊆B always true??" plz gib proof without using counter example or trivial cases like assuming A=C and showing it isn't always true. I need a set theory type proof iykwim

>>16749831
Maybe the following is what you're looking for.
N = Sec[2 α] (D Sin[α] Sec[ψ] + L Cos[α])
A = Sec[2 α] (D Cos[α] Sec[ψ] + L Sin[α])
S = Sec[ψ] (C – D Tan[ψ])
If not, then I hope, that someone else chimes in or gets involved.

>>16749946
You’re talking about applied electromagnetism. I’m talking about the theory.

>>16750072
Which theory? Maxwell's Equations are "solved". Quantum Electrodynamics is "solved". If there is something beneath that we haven't discovered it.

>>16750074
Then all modern research really is all quantum mechanics variants…

>>16750079
Yes. Were you expecting something else? Classical physics is all simply quantum mechanics underneath.

>>16750099
I don’t believe in quantum mechanics, there’s no experimental proof of it, it’s just like evolution, just a bunch of crap that scientists made up to explain stuff that haven’t been fully understood yet.

>>16750118
Shit like the uncertainty principle makes no fucking sense in the real world, that’s what I’m talking about. Show me proof that the movement/state of a particle changes whether or not someone is observing, that’s shit is so comical, so fantastical, that you might as well start believing in Santa Claus.

>>16750133
That's great anon. Clearly you alone know better than over a century of scientific research and experimentation. You keep doing you.

>>16749932
static electricity is still fucky as far as i know

How would you explain to an alien the concept of "time"? Is it possible time is just a distance calculation humans made up and we cannot seem to admit its madeup nonsense based on how long our specific planet takes to move?

>>16750164
Notice how he still hasn’t shown the experimental proof I’ve been asking for three posts now. I rest my case.

>>16750133
>Show me proof that the movement/state of a particle changes whether or not someone is observing
That's the observer effect and not the observer effect, dingus. It follows immediately from the fact that light has momentum, demonstrated by Compton, and basic kinetics.
Seeing an object is actually seeing light reflecting off of it. Unsurprisingly, this applies for particles, too. Because the light's direction of travel changes, so does its momentum, and to conserve total momentum your observation has affected the particle's momentum as well.

Is that sufficient for you?

>>16750208
*not the uncertainty principle
At some point I should learn to proofread after rephrasing things.

>>16750208
That’s not experimental proof, that’s just theoretical babble, you may think mathematical proof = truth, but it doesn’t, it’s only valid in a piece of paper or in your imagination. I’m asking you to show me images or videos of what your claiming to be true.

>>16750217
And what are you expecting to "see" from such a video? Especially since the acting of "seeing" is itself a measurement and hence fixes the particles state. In actuality there are no physical examples of the uncertainty effect. It is a mathematical inequality about how accurate any observation / measurement can be.

[math]\int_x\left[\int_{x,y} g(x,y) ~ f(x,y) d(x,y)\right] f(x)dx[/math]
Can this double expectation be collapsed into a single expectation?

>>16750247
To clarify, (x,y) is two independent draws and x is a single draw. So the inner expectation is over pairs of draws and the outer expectation is over a single draw.

>>16750133
>Show me proof that the movement/state of a particle changes whether or not someone is observin
It's not about "someone observing."
Forgive the veritasium, but here's experimental proof It's a real thing:
https://youtube.com/watch?v=a8FTr2qMutA

>>16750247
I'm unable to parse what you wrote.
Firstly, don't use the same dummy variable for nested integrals; it's currently impossible to determine, for example, whether the x in g(x,y) is being integrated over by the inner or the outer integral.
Next, you use the function f (I assume it's a density) both as a one- and a two-argument function. If you have independence the inner part should probably be f(x)f(y).
Thirdly, you put your dummy variables in the subscript if the integrals, which I don't really understand.
If I got things right, the inner integral is just a scalar, and the outer integral is just 1 if you take it out, so it'd already be "one expectation".
Maybe you meant something else?

>>16750259
What's wrong with Veritasium? It’s a great channel, the best!

>>16750343
He's Reddit incarnate.
"I love science" combined with saccharin sweet starry eyed optimism that makes me want to puke.

>>16750247
>Can this double expectation be collapsed into a single expectation?
Is there a dependency between x and y for the functions g and f?

>>16750385
>he thinks people that post on reddit are starry eyed optimists
The fuck are you smoking, no they're not even fucking remotely like that

I am in deep shit please help.
I am writing my thesis.
I did all my design work and experimentation. It was fun, I found out new stuff. I have results.
I can not write. I am distracted, unmotivated, I can not write coherent paragraphs. It has bo structure. I make redundant and superfluous statements. It's a clusterfuck. I go onto YT or 4chan and check if any threads bumped or any happenings. No.
Fuck.
I have one month left.

>>16750452
Reddit is Enid, 4chan is Wednesday.

How would fire react under higher atmospheric pressure, 4 to 6 bar? Would it burn even more? Yes right?

>>16750513
Just shit out your ideas on paper then go back and edit it later.
Or use ChatGPT like all your classmates ate undoubtedly doing.

>>16749961
boomp for this

>>16749961
>>16750776
What are you asking for? Your statement is false, so a counterexample is enough to show [math]A\subseteq B[/math] isn't *always true*.

>>16749961
>is ... always true??" plz gib proof without using counter example
>I need a set theory type proof
In set theory like in all the rest of mathematics. The usual way to prove that a certain property is not always true is through a fucking counter example.

Do chemical compositions change their interaction on electrically insulated situations?

Understanding electricity as the fully electromagnetic spectrum

>>16750790
is it possible to prove it using proof by contradiction or a proof where the mathematical arguments laid out show that it isn't always true? I just need a proof of this type m8 (which I can't follow and I fear it might wrong). Btw what is the name of proving things in this fashion??

>>16750811
it's from gemini btw

>>16747955
You take notes, and look back at them when needed. Nobody remembers everything

What are the homology classes for this thing? I'm getting Z, 0, Z, since this is basically a sphere with a surface in the middle, but that doesn't change anything

If gravity is not a force but a curvature of spacetime, why do we accelerate as we fall? Wouldn't we expect to fall at an almost constant velocity?

>>16750588
Yes. This is basically why the compression stroke exists in engines.

>>16751666
The curvature gets steeper as you get closer to the center of mass.

>>16751675
>The curvature gets steeper as you get closer to the center of mass.
But if you drop a ball from a 100m height and one from a 10m height, the one dropped from 100m will reach a higher maximum velocity before hitting the ground.

>>16751689
Yeah. It's called momentum.

I'm not trying to be a dick here, just hoping that making it sound obvious will make it "feel" more obvious to you.
Smacking something for a quick instant vs. applying continuous force. Except the "force" is just following a straight line along a spacetime geodesic.

>>16751690
>Yeah. It's called momentum.
But the momentum of both is 0N, right? Neither is undergoing acceleration with respect to the local spacetime, and the force of the collision when they hit the ground is really the earth accelerating outwards.
>I'm not trying to be a dick here, just hoping that making it sound obvious will make it "feel" more obvious to you.
It still doesn't feel very obvious to me, sorry. Maybe I'm stupid, but the Newtonian description makes more sense to me than the General Relativity one.
>Smacking something for a quick instant vs. applying continuous force. Except the "force" is just following a straight line along a spacetime geodesic.
But both are following a straight line, right? Is it just that they're at "different angles"? I don't think time dilation is sufficient to explain the difference.
Or is there some reference frame illusion going on that accumulates momentum without acceleration? I thought that accumulation of momentum is what acceleration *means*.

>>16751710
>I thought that accumulation of momentum is what acceleration *means*.
This is the misunderstanding. There are two different notions of acceleration: coordinate acceleration which is the more classical notion, and proper acceleration as defined by GR. In flat spacetime they are the same, but in a gravitational field, coordinate acceleration is constant while proper acceleration remains at 0. When people say that you are not accelerating in free fall they are using a different definition of acceleration and being a little obtuse.

>>16751725
But where does the coordinate acceleration come from? The metric tensor? What would that mean physically?

Did the british government postpone the ban of 4chan and other pages?

>>16751779
They never said they were going to ban it in the first place

Is it a fallacy to assert that life must be common because we exist? i.e. because life exists, it must be fairly probable for it to occur.

In scenario A, life developing in the universe is extremely common, and we are one of many lifeforms.
In scenario B, life is extremely uncommon, and life on earth is an .

Can we use this to say that it is more probable that life is common, or can we say nothing because we don't know the probabilities of A and B? Does the anthropic principle refute this this argument- if we weren't here, we wouldn't be able to make a claim about the probability of life.

>>16751916
> we say nothing because we don't know the probabilities of A and B?
This. It's what formula like the The Drake Equation try to quantify but we currently have no way to determine any of the parameters.

>>16751916
I would say yes, it's a fallacy. In a universe with only one sentient species, they could very well make the exact same assertion. All we can say is that if there are only finitely many universes, the frequency with which complex life emerges is non-zero.

>>16751834
Do they need to upload their IDs or something like that?

I wonder if there are colors out there, or fuck even here that are beyond what the human eye can comprehend

>>16751975
We don't know yet. Ofcom are "investigating" 4chan, along with a billion other sites, but no news beyond that.

>>16752044
https://www.sciencealert.com/scientists-say-they-found-a-new-color-humans-have-never-seen-before

>>16752053
Holy shit

I have a mathematical question, but I'm too lazy/stupid to do the math myself and AI doesn't give me a proper answer (maybe I'm not prompting properly). I wonder if you guys can help me.
The hypothetical case is the following.

A house is worth $300,000. There are 200 people that know each other and are cooperating. Every month they give $150 each to one person to buy a house, the first person being able to buy the house in 10 months. Imagine that everytime a house is bought, 4 people of the 200 move in and start giving $1000 to another of the remaining 196. How long will it take to buy 50 houses so that the 200 people are no longer homeless or rent slaves?

>>16753182
>AI doesn't give me a proper answer

>>16753186
What? Everyone is always saying how AI can solve complex math problems and even prove theorems by itself.

>>16753189
Yeah, that's mostly bullshit.

Does anyone know how to read geometry

>>16753182
>are no longer [...] rent slaves
they will still be property tax slaves

>>16753182
>Imagine that ever[y t]ime a house is bought, 4 people of the 200 move in and start giving $1000 to another of the remaining 196.
This isn't clear.
>AI doesn't give me a proper answer (maybe I'm not prompting properly)
Maybe is right.

If you are travelling 2x the speed of sound towards someone and are emitting an audio signal, will they hear it in reverse?

How do I win at math bros?

>>16753858
Its not called a sonic moob is it?

libgen.is is down where do people download books now?

What's to stop a basement scientist from like creating a super virus and releasing it?

>>16754210
Most people competent enough to do that aren't fucking psychos.
Other than that, nothing other than "It's hard to do."

>>16754029
annas archive
>>16754210
biotech people take their bioethics course seriously - there's a reason why bioweapons are not much of a thing desu. Other than that, it's hard to make pathogens safely, and people wanting to make pathogens as a prank are often not suicidal.

How seriously people take their ethics in STEM goes something like:
Computer Engineers/Scientists/Physics < Chemists < Biochems/Biotech/Civil Engineers

(source: made it up)

if i'm given the vertex (h, k) and a random point on a parabola (x, y), how to i use it to find the general form of the quadratic function: [math]ax^2+bx+c[/math]

obviously i can plug h and k into the standard form [math]a(x-h)^2+k[/math], but i don't know how to use the other point (x,y) to find a

>>16754712
i think i might have figured it out on my own, i can plug x and y into it and solve it algebraically
[math]\frac{y_1-k}{(x_1-h)^2}=a[/math]
then i can just expand the standard form into the general form

>>16754405
Software engineers deserve the lim-inf tier

Software Engineers < Computer Scientists < Mechanical/Electrical/Computer Engineers < Physicists/Mathematicians/Natural Sciences < Chemists < Biochems/Biotech/Civil Engineers

source: visit san francisco and see for yourself

>>16754712
https://www.wolframalpha.com/input?i=Solve%5B%7Bk+%3D%3D+a+h%5E2+%2B+b+h+%2B+c%2C+0+%3D%3D+2+a+h+%2B+b%2C+v+%3D%3D+a+u%5E2+%2B+b+u+%2B+c%7D%2C+%7Ba%2C+b%2C+c%7D%5D

How muich wind energy would we have to extract for it to cause climate impacts on the earth? For example, any wind turbine is converting wind energy into mechanical/electrical energy, removing the wind energy. Eventually impacting the wind would cause changes in jet streams or something maybe. Would this amount be something we could ever achieve in the next century or would it require like a turbine every five feet on the whole planet

>>16754712
equation of parabola:
(y – k)/(v – k) = ((x – h)/(u – h))^2

If (x, y) = (h, k), then the equation becomes 0 = 0^2.
Thus the parabola passes through the vertex (h, k).

If (x, y) = (u, v), then the equation becomes 1 = 1^2.
Thus the parabola passes through the other point (u, v).

>A metric space (X, d) is said to be compact iff
every sequence in (X, d) has at least one convergent subsequence.
Does this mean that the point the subsequence converges to is necessarily in X?

>>16756023
X is closed.

>>16756033
Do those sequences need to be infinite or are finite sequences also valid?

>>16756023
In this context and phrasing, yes. X is a whole space and 'convergent subsequence' only makes sense in X if we know there is a point in X which it converges to.

But I think there is a notational subtlety and ambiguity here which amounts to whether our metric space X is ingrained in another space and so if a limit in X can be meaningfully said to converge to a point outside X. In real analysis, we have context of say a space A as a subset of R, so a sequence in A can be said to have a convergent subsequence when considered in R, but A itself need not contain that limit.

So perhaps confusingly, you might see in some books (like Abbot) that in the Bolzano-Weoerstrass theorem, given a bounded space A, each sequence s_n has a convergent subsequence s_{n_k} whose limit may not reside in A. Compactness says it has such a limit and it resides in A.

But for an arbitrary metric space X you are working in, there are no points outside X so this kind of phrasing doesn't make sense. Every sequence and limit would reside in X: this makes a slight divide when talking in a real analysis sense and a metric space topology sense.

So if AI starts replacing code monkeys, doesnt that mean we just make more EE jobs to cover energy demand?

supposedly we know 300 trillion digits of pi calculated in 75 days. any reason why that stopped and they didnt continue to spit out more numbers?