/sqt/ /qtddtot/ - stupid questions thread

[Anonymous No.15017870]

Previously >>15004641

>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
z-lib.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.15017896]

Unanswered questions:

Maths questions:
>>15015147 [Follow up in >>15015150]

Physics questions:
>>15010106
>>15010734
>>15010824

Chemistry questions:
>>15014737

Engineering questions:
>>15008486

/g/ questions:
>>15011964

Stupid questions:
>>15005687
>>15006331
>>15007643
>>15010687 [From now on, if you screenshot a proof in your textbook and don't include the theorem statement your question goes in stupid.]
>>15011654
>>15011878
>>15011924
>>15011974
>>15013113
>>15015847

[Anonymous No.15017920]

[Anonymous No.15017962]

In the geodesics equation, how do you go around showing that lowering the indexes switches out the + for a -?

[Anonymous No.15017988]

>>15017962
Elaborate.

[Anonymous No.15017989]

>>15014737(Cross-thread)
lolwut? they trade protons in an equilibrium, they interact constantly

[Anonymous No.15018044]

>>15017962
>>15017988
Nvm, just realized the book's author was just abusing notation (probably given due to how you might as well just treat the dual space as equivalent to vector space), and had added a -to how the Christoffel symbols were being defined, switching the sign on the equation.

[Anonymous No.15018057]

>>15018044
Are you sure it's that?
Identifying a space with its dual is exactly the kind of abuse of notation physicists know not to do, which is the whole point of index juggling.

[Anonymous No.15018059]

>>15018044
The double dual is a equivalent, not just the dual.

[Anonymous No.15018069]

>>15017870
> >tables, properties and material selection?
> No NIST
kek

[Anonymous No.15018083]

Thoughts on Lang's linear algebra? I like dense books which don't waste time and just go straight to the point, which seems to be the main reason most people don't like it

[Anonymous No.15018087]

>>15018059
The dual is canonically equivalent in spaces equipped with inner products (non-degenerate bilinear forms really), it's just not the kind of equivalence you use implicitly (instead, you use it explicitly by raising and lowering indices).
>>15018069
That listing is literally two links furfag threw in plus the chemspider link I saw pc98fag posting all the time.
>>15018083
>Thoughts on Lang's linear algebra?
I learned linear algebra from it.
It's not bad but I wouldn't recommend it either.

[Anonymous No.15018107]

>>15018083
Haven't read it, but if you want a very terse and very comprehensive Linear Algebra book (also very cheap) that does not waste any time, I would recommend Bhimasankaram & Rao. Btw Axler is the opposite of what you want, and there are two books my Lang.

[Anonymous No.15018201]

>>15018069
>>15018087
The best reference for materials and properties i know is the "CRC Handbook of Chemistry and Physics", you can get the 97th edition from libgen, though i'm not sure how comparable it is to NIST as i've never used the latter.

[Anonymous No.15018229]

>>15018201
For example:
https://webbook.nist.gov/chemistry/fluid/
https://webbook.nist.gov/cgi/cbook.cgi?ID=C62533&Mask=200
Although probably you can find anything, from coefficients to charts always with good data and sources. Also has option to export data to use it in programs directly.

This isn't NIST but it's useful for its niche:
https://refractiveindex.info/

[Anonymous No.15018248]

https://www.youtube.com/watch?v=1j7bMsFogJE
>room temp superconductor
Fuse it with diamagnetism, Energy cost/benefit equation?

[Anonymous No.15018266]

>>15018248
Diamagnetic != superconductor. Bismuth isn't a superconductor.

[Anonymous No.15018296]

How can I check if a graph (pic rel) is planar?

[Aether king of sci No.15018300]

>>15018296
HAHAHAHAHAHA YOUR PIC RELATED. THE FUCK IS THIS? LOL LFMAO

nice shape bro

>And for the end of this semester will everyone present a shape they created
>OP
>H...here goes

[Anonymous No.15018331]

>>15018300
Huh? It's a graph and I need to check if its planar. Is this not the thread for help on problems?

[Aether king of sci No.15018340]

>>15018331
Yeah but you need more than help, you need a fucking miracle LOL

[Anonymous No.15018346]

>>15018331
ignore namefags, theyre all schizos. the avatarfags are your friends.

[Anonymous No.15018347]

>>15018296
euclids formula
v − e + f = 2
f being faces aka the number of closed surfaces (triangles, rectangles, pentagons etc etc)
if the result is any other number other than 2 its not planar

[Anonymous No.15018356]

>>15018346
thanks, will do
>>15018347
Thanks but is this sufficient? Textbook talks about Kuratowski's Theorem to confirm if a graph is planar and it involves more work but if we can conclude the same from eulers formula then whats the point of the theorem?

[Anonymous No.15018363]

>>15018356
>>15018347
>Euclid's formula
Euler's, and it doesnt work because you don't a priori know the number of faces, and can't bound it because there is a valid planar drawing if you switch two edges around.

Kuratowski is the way to go, you can find [math] K_{3,3} [/math] as a subgraph without too much trouble (I don't want to draw it)

[Anonymous No.15018368]

>>15018347
>>15018356
You can only apply euler's formula if you can embed the graph in some space without any intersecting edges, it's useless here.
>>15018296
This graph is not planar, you can check that using Wagner's theorem, the complete bipartite K3 graph is a minor of this graph.
https://en.wikipedia.org/wiki/Wagner%27s_theorem

[Anonymous No.15018373]

>>15018368
>>15018363
Thanks anons

[Anonymous No.15018645]

Ok guys, I am hardstuck on something for work.
How do you go from the first line to the second one on picrel? The person seemingly swapped both integrals, so at first I thought she was using Fubini's theorem, but the boundaries also changes.
Am I retarded? She just went from one line to another like it's some easy shit, but I cannot understand what she did. Can anyone help me understand please?
Some more info it is helps : [math]x_0 > 0[/math] , [math]x > 0[/math] and [math]y > 0[/math] . Also [math]u(x_0,t) = 0[/math]

[Anonymous No.15018655]

I'm playing with dynamical systems
let's say I have a system of differential equations like
[math]\dot{x} = y + z\\
\dot{y} = x - z\\
\dot{z} = y - x\\
[/math]
or something, it doesn't matter.
I know I can "hand solve/integrate" this by picking initial values for x, y, and z, and then just iterating through the equations, feeding the answers back into the variables. Assuming each iteration is a single time unit, I can only ever discretely evaluate this system. As in, I can evaluate for when t = 0, 1, 2, 3...
I want to know how I can "decrease the timestep" when evaluating a system. That way I can get t = 0, .00001, .00002, and so on. How is that achieved?

[Anonymous No.15018656]

>>15018645
It is fubini. You can work it out as follows:
At first you have the constraints [math] 0 < z < x - x_0 < \infty [/math], and integrating over a variable means taking the tightest bound and then dropping it from these constraints. So you integrate over [math] z [/math] first: [math] 0 < z < x-x_0 [/math]. Then you get [math] 0 < x-x_0 < \infty [/math], which is the top line.
If you integrate over [math] x [/math] firtst, you get [math] z < x-x_0 < \infty [/math] and then [math 0 < z < \infty [/math].
Drawing pictures also helps often.

[Anonymous No.15018668]

>>15018655
Just divide each time unit by 100,000 and you'll have it.

[Anonymous No.15018673]

>>15018201
Sounds good, I'll link it later.
>>15018655
Just google the Euler method.

[Anonymous No.15018771]

>>15018656
ohhhh I think I get it! thank you.

[Anonymous No.15019074]

Will mathematicians ever discover a method to determine why mathematics is so gay?

[Anonymous No.15019296]

What minimum distance from Earth's surface should I orbit so that I always see the sun?

Asked another way: if I want to set up a solar power array in orbit that transmits power to the earth's surface, what minimum distance from Earth's surface allows uninterrupted, 24/7 power (if this is even possible)?

[Anonymous No.15019341]

It makes sense that a fever makes you feel cold since your body is warmer than the outside. But if you have a fever of +5 degrees, it feels much colder than if the air were -5 degrees at normal body temperature. Why?

[Anonymous No.15019431]

>>15019074
They have.

[Anonymous No.15019638]

Does the definition of limit point compactness require that every infinite subset A of a limit point compact set X to have a limit point in A? Or does it only require there to be a limit point in X?

[Anonymous No.15019640]

>>15019638
Disregard this. Found the answer in another text.

[Anonymous No.15019772]

how do i know when im supposed to use the direct comparison test vs the limit comparison test? for #25 i was supposed to use the Direct Comparison Test and #26 was supposed to use Limit Comparison Test
how do i know which one was which?

[Anonymous No.15019786]

how do i calculate thembo inches? asking for a math science fair project. im trans BTW

[Anonymous No.15019787]

>>15017870
Can you prove 2+3=5 like cobson did?

[Anonymous No.15019831]

>>15019772
Direct comparison works if you have a seried that can be easily compared to a well-known series.
e.g., [math]\frac{1}{5^n+1} \leq \frac{1}{5^n}[/math], the latter is a classic convergent geometric series so it follows that your series convergent.
You can't easily do that with the second one, but you can easily work something out with limit comparison and another, similar convergent series.

[Anonymous No.15019947]

>escape velocity or escape speed is the minimum speed needed for a free, non-propelled object to escape from the gravitational influence of a primary body, thus reaching an infinite distance from it.
If I gently toss a tennis ball up in the air, on its way up it has enough velocity to go against the gravity of the earth, ground level air friction, etc to rise.

I dont know the speed of gently tossing a ball up but im sure its way less than the Earth's escape veloctiy. If there was a rocket on the tennis ball to keep it going indefinitely at the same speed my arm throws it at, and it continues up in the same direction, what is stopping it from escaping earth?

[Anonymous No.15019948]

>>15019831
But
[eqn]
\frac{1}{n^3 - 8} \leq \frac{1}{(n-2)^3}
[/eqn]

[Anonymous No.15019982]

>>15019296
You'll never get 100%. Whatever orbital plane you choose, there will always be two points in time each year when the sun crosses the orbital plane. When the array passes the opposite point from the sun, if the sun is close enough to the orbital plane the array will be in shadow. If the orbital radius is large enough, you may miss the shadow completely some years: if the array is on the daytime side of the earth as the sun crosses the orbital plane, the sun may be far enough off the plane when the array is on the nighttime side. On other years, it will hit the shadow. How often this happens is close to a straight inverse proportion; the higher the orbit, the less often it happens.

The mathematics is the same as for a lunar eclipse, except you can choose the orbit; a polar orbit is better than an equatorial orbit, as you get almost 6 months without it happening at all.

[Anonymous No.15019990]

in coding like python/c++, what's the next step after learning classes/inheritance/loops?

[Anonymous No.15020325]

is time a vector

[Anonymous No.15020372]

so i wanna impress my druggie friends and bring ether to a party but it's illegal and i'm too scared to steal it from the uni lab, is there a way i can make it at home? my dad has a lot of 40%ish percent booze, can i chuck in any strong acid and heat it at 130 ish celsius? won't ethanol and water evaporate? what worries me more is, wouldn't the ether explode?

[Anonymous No.15020379]

Where the fuck did the vocal cords in mammals and the syrinxes in birds come from? How did terrestrial tetrapods go from straight breathing tubes to sound-making organs? And for the sake of specevo autism, how would such an organ arise again?

[Anonymous No.15020649]

can you guys give me a good youtube video that goes over like most or all of series & sequences for calc 2? i need to review it

[Anonymous No.15020840]

>>15020649
Here you go...

https://www.youtube.com/watch?v=jTuTEcwvkP4

[Anonymous No.15020849]

>>15019990
Learn data structure, algorithms, operating systems, discrete mathematics.

[Anonymous No.15020852]

>>15020840
bro thats 6 hours...
are you trolling? is there another one?

[Anonymous No.15020948]

>>15020852
>>15020649
Yes, there are others...but there's nothing like
going over most or all the series for calc 2 than this.

>just skip around

Also, I meant to give this:

https://www.youtube.com/watch?v=XdkoTb8PEG0

[Anonymous No.15020951]

does being/going blind affect spatial IQ?

[Anonymous No.15020956]

>>15017870
Bumpy

[Anonymous No.15020969]

>>15019947
Nothing. Escape velocity assumes an acceleration only due to gravity and a rocket would be additional acceleration.

[Anonymous No.15021055]

Explain to my small brain why karnaugh maps are built like this, specifically the 00 01 (11) 10.
I searched online and it had to do with gray code but i forgot gray code because i too that ages ago

Also non related but i want to fully know everything from computers from advanced architecture to parallel processing and things like that so how much digital logic should I learn to fully understand these things?

[Anonymous No.15021209]

>>15019990
Data structures and algorithms. I.e. programming. If you compare the job of a programmer to that of an author, learning the syntax and semantics of a programming language is like learning to use a typewriter. A language is a tool used in the job, but the job also requires some fundamental skills which are largely unrelated to the language.

Learn the various container classes; how they differ on a functional level (e.g. vectors and lists preserve order and can contain multiple copies of an item, sets don't and can't) and also a non-functional level (lists allow O(1) insert and delete at any point, vectors allow O(1) push/pop but are O(n) for insert/delete in the middle). Get a basic understanding of how they're implemented for when you need to design your own data structures.

Learn some common algorithms. Sorting, searching, graph traversal. How to break a problem down into individual steps.

[Anonymous No.15021248]

>>15019990
Try-catch, listcomps, magic methods, dictionaries, virtual functions and classes, operator overloading, references, move semantics, shared pointers, templates, RAII, allocating and freeing memory by hand, IO operations.

[Anonymous No.15021411]

>>15021248
how do you know so much about math, physics and computer science? are you some kind of genius?

[Anonymous No.15021532]

>>15019982
Thank you.

[Anonymous No.15021673]

>>15020849
>>15021209
Man, I've been trying to avoid DSA but it seems like it's time to finally hit it up. I'm not a CS student, just a regular engineer student who's been avoiding coding like the plague but eventually realized that it's too useful to not learn eventually.
>>15021248
Dad I only know half of those words but I'll figure them out eventually.

[Anonymous No.15021718]

/sci/ i'm defending my dissertation in a week

[Anonymous No.15021739]

>>15021718
good luck uwu

[Anonymous No.15021859]

how does (2n+1) turn into (2n+3) ???
n+1 just adds a +1 to the n, so why is it 3? shouldnt it just be (2n +1 +1) which is (2n+2)
what happens if its something else? is there a rule im missing?

[Anonymous No.15021874]

>>15021859
also, what cancels with (-1)^(n+1) im literally so confused

[Anonymous No.15022032]

>>15021055
Because cells which only differ by one bit are adjacent (including wrapping around at the edges).

xy: 00 01 11 10

x: 0 0 1 1
y: 0 1 1 0
¬x: 1 1 0 0
¬y: 1 0 0 1

This makes it easier to identify chunks of the map where a specific bit doesn't matter.

[Anonymous No.15022037]

>>15021859
All you do is replace n by n+1, so

[math]2(n+1) + 1 = 2n + 3[/math]

>>15021874
You forgot about the absolute value sign

[math]|(-1)^{n+1} / (-1)^{n}| = 1[/math]

[Anonymous No.15022050]

So any science lads here or med fags know how to mend micro cavities and kill off current ones? I'm not wanting to be jewed hard by my local dentistry plus any tricks for how to boost enamel without over doing it?

[Anonymous No.15022206]

>>15021673
I basically just spammed a bunch of C++/Python language features at you since the other two anons gave very generic answers.

The really, really important ones for C++ are references and move semantics. If you don't use references and move semantics correctly your C++ code is liable to be as slow as python.
>>15021718
Good luck.

[Anonymous No.15022217]

The only languages mathematicians should learn are C, Lisp and Haskell.

[Anonymous No.15022233]

>>15022032
Sorry you didn't explain shit or I just can't find the pattern, I know how k-maps work but why. why do we care about about cells which differ by one bit?

>This makes it easier to identify chunks of the map where a specific bit doesn't matter

Ok after thinking about it for a bit. The goal of K-maps is to simplify the sop or pos and the only way to do this is by using the Null, identity law
Or in simple terms our goal is to get like x'y'+x'y = x' and the only way to get this is by ignoring the variable that has changing bits but to visualise that better we switched the 10 and the 11 columns so they can be adjacent?

[Anonymous No.15022246]

>>15021055
K-Maps is a clever technique of factorization in digital algebra. It's arrangement is done like that because it allows for easier recognition of common factors.

>>15022217
This is 'stupid questions thread' not stupid advice thread.

[Anonymous No.15022390]

>>15022233
> Or in simple terms our goal is to get like x'y'+x'y = x' and the only way to get this is by ignoring the variable that has changing bits but to visualise that better we switched the 10 and the 11 columns so they can be adjacent?
Yes. With up to four bits of input, any product (AND) of any combination of the input bits or their complements forms a contiguous rectangle (possibly wrapping around at the edges). For a 4x4 grid, a single bit or its complement is a 2x4 or 4x2 rectangle; a product of two bits is 1x4, 2x2 or 4x1, while three bits is 1x2 or 2x1. This simplifies producing an expression in DNF (minterms, sum-of-products) with the minimum number of terms.

[Anonymous No.15022509]

I don't comprehend the equation for the curl operator. I don't get it.

[Anonymous No.15022539]

Is khan academy good place to learn math?

[Anonymous No.15022628]

>>15022509
What's to get? The equation is its definition.

[Anonymous No.15022630]

Given a path connected space X, what are some sufficient conditions for a subset of X to also be path connected? No need for proofs or anything.

[Anonymous No.15022691]

Does any know what I just saw, or can help me find info about it?

@18:40 I saw a bright green regular pulsating light fly across the sky, it was brighter than ISS@-6.
It was also way faster but that could be a illusion from a lower altitude but by looking at its speed and not hearing a sonic boom it must have been in space.

I live in the Netherlands and saw it to the west of me and it flew past from south to north and it crossed the observable sky within 20 seconds, I've seen anything in my life go that fast.

[Anonymous No.15022711]

>>15022539
Good up to Calc II. From there just read textbooks

[Anonymous No.15022731]

>>15018296
its planar

[Anonymous No.15022768]

>>15022628
what is the definition for 2d curl?

[Anonymous No.15022799]

>>15017870
Are combinators related to combinatorics? Recently I was given a Wolfy book about Combinators.

It looks like to use them you write the letter S and the letter K a lot of times and it makes a tree somehow.

Is this going to relate to counting somehow? Wolfy unfortunately based her work in this book off a German maid called Flugelhorn, so there is German technical writing in this Wolfy book and I don't like German because it is a Clown Language unfit for human speech.

[Anonymous No.15022948]

>>15022691
best I can think of is https://en.wikipedia.org/wiki/Green_flash
how high above the horizon was it?

[Anonymous No.15023593]

>>15022768
Curl is only defined for R^3.

If you have a function f:R^2->R^2, f(x,y)=<Fx(x,y),Fy(x,y)> and you extend it to g:R^3->R^3, g(x,y,z)=<Fx(x,y),Fy(x,y),0> then the z component is always zero, the partial derivatives w.r.t. z are always zero and the curl will always be in the Z direction: ∇×g=<0,0,∂Fy/∂x-∂Fx/∂y>.

[Anonymous No.15023632]

someone posted this. Wouldn't the body provide some of the calories for getting to the right heat?

[Anonymous No.15023635]

>>15022799
> Are combinators related to combinatorics?
No. It's a Turing-complete model of computation similar to lambda calculus.

[Anonymous No.15023645]

x is bounded by some constant positive integer A, and y is bounded by A(A-1)/2.
Given A, are there integers a,b such that x and y can be computed from a*x + b*y?

[i know this is a really extremely low quality post, but.. No.15023661]

Does my pikapede pass?
Eyeballs on u?
One does not simply enter into mordor?
Wood hecc agin?
heel at command?
gay footstool joke?

[Anonymous No.15023668]

>>15023632
That pic is so pol/tard.
1. The energy needed to heat a "body" to 870ºC is ~4700J/g. I'm not gonna fed poltard on how is the correct calc.
2. The body has an equivalent to ~35% dry mass CHO, that alone is enough to completely turn all the body in ashes in gas without any added energy or heat recovery system.
3. The amount of cremated people was lower, but that doesn't matter because that pic is about poltards being retards, also:
4. Even if I take those numbers, 6 millions, 24M tons of ash, that is 3 train/truck wagons a day in just one year, nazis had a lot of resources even at the end of war. Of coal ignoring the 2, you only need 7 wagons a day for all the camps.
5. irl those people weighted less than 50kg.

In the middle ages adult pigs/cattle was used as "mobile fuel" in sieges, under the right circumstance any animal is flammable enoough to turn itself in a red hot kiln capable to destroy a stone wall/bridge/gate.

Those poltards are seriously retarded, can't even do basic math.

[Anonymous No.15023672]

>>15023668
Now that I see it they are so retard that instead of writing 236624.5 KJ they converted (on purpose probably) KJ into Kcal. The absolute state of poltards.

[Anonymous No.15024048]

i am >>15020649 and
>>15020852

i have an exam on series tomorrow
can you guys send me more youtube videos on series?
like ones that go over all of them

[Anonymous No.15024189]

did anyone else just get perma b& after posting in that prime number thread? i think they might've hit the "nuke all posters" button.

[Anonymous No.15024206]

>>15022711
>Calc II
Is Calculus II single-variable integral calculus, or is it multivariable calculus? It looks like KhanAcademy has videos for both, and even some for differential equations and linear algebra.

[Anonymous No.15024411]

>>15024206
It would be single variable, unless the professor
throws in an introduction to multivariable functions
at the end.

[Anonymous No.15024543]

>>15024189
test

[Anonymous No.15024885]

>>15024189
4chan.org/banned

[Anonymous No.15025057]

esl here
what is meant by polar diagram of a complex function?
is that real vs imaginary or something? google sucks

[Anonymous No.15025094]

>>15025057
You draw the function on the complex plane.

[Anonymous No.15025104]

>>15022948
it definitely wasn't natural, it flew across the whole sky with about 2sec of light on and off flashing.

I would say about 45° maybe a little higher.

[Anonymous No.15025108]

is this true or am I tripping?

[math] a \equiv b \mod{m} \land a^{k} \equiv b \mod{m} \implies a \equiv b \equiv 1 \lor a \equiv b \equiv 0 \mod{m}[/math]

[Anonymous No.15025126]

>>15022691
>>15022948
>>15025104
AVADA KEDAVRA

[Anonymous No.15025145]

>>15025094
I figured that was the case but this problem is asking me to plot it vs the argument of the function but its meant to be a 2d plot
Im no expert but 3 axes into 2 dimensions doesnt fit

[Anonymous No.15025159]

>>15025108
It's wrong.
Consider
a=2
b=2
k=11
m=341

[Anonymous No.15025166]

>>15025145
What are C and S?

[Anonymous No.15025168]

>>15017870
CONTEXT: I am completely maths illiterate, I did not even take Algebra and Trig in Highschool. So when I say I am starting from scratch I REALLY mean it.
So I have been learning to code recently, and have actually enjoyed myself and have made good progress. However, I recently started a project that requires working knowledge of Estimation statistics (a complex American election simulator that does a governor and senate election for each state) and oh boy was I filtered hard. Its not that I cannot figure out how to program the maths. The problem is that I do not know how to come up with the maths in the first place. For example I want to have multiple changing variables that infleunce the outcome of the race, such as the approval rating of the incumbant and the president, multiple political issues such as the economy and education etc. But I really cannot put all the pieces together. I have always wanted to learn about Probability and statistics, but I was too retarded to follow through in school. I feel like if I just pick up a probability textbook I won't go anywhere.
So where do you think I should start to be able to eventually understand and use Estimation statistics?

[Anonymous No.15025222]

>>15025166
theodorsen and sears functions
theyre made up of a combination of third type bessel functions

[Anonymous No.15025281]

>>15025222
Just use W as the X axis and plat the graphs.

[Anonymous No.15025286]

>>15025145
Either use two different plots for magnitude and phase each, or plot the polar diagram and show the values of 'w' at intersections and other random points.

[Anonymous No.15025323]

>>15025168
Ideally you would get data on the things you mention (approval rating / state of the economy / ...) and on race outcomes and just dit a glm to get a way to predict those outcomes, but I assume that's not possible, so why not just make up a simple model? Say, if candidates a and b have approval ratings r and s, then you could just make the assumption that the probability that a wins is r/(r+s), for example.

[Anonymous No.15025326]

>>15025323
>dit
fit

[Anonymous No.15025348]

>>15025323
Oh, because I already have done a basic version of this and it works perfectly fine. Now I want to simply scale up.
To tell you the truth I am a bit over ambitious given my limited skillset. The kind of coding I am doing is for enterprise computing (Cobol, Rexx, Java etc). I want to use the I/O capabilities of the mainframe to basically create a playground where you can run the model and tweak it in real time.
The point of this is to also explicitly learn estimation stats. So I want to have a script that say writes me 5000 'mock poll questionaires', so I can use them to extrapolate and calculate "margin of error" the same way the real pollsters do. Seeing things in motion makes learning a lot easier for me. The point is I would also LIKE to learn this field of stats, and am up for the challenge. I just need to slowly work towards it.

[Anonymous No.15025369]

So people say suicide is selfish, would a good counter argument be that it is also selfish to forcibly bring a person into this world?

Also would the problem of induction be considered a fallacy?

[Anonymous No.15025394]

>>15025369
>>>/adv/ >>>/lit/

[Anonymous No.15025396]

>>15025369
>would a good counter argument be that it is also selfish to forcibly bring a person into this world?
No. That's altruistic, not selfish. A good counter argument would be "yes but so what?"

[Anonymous No.15025402]

>>15020951
Nope, you just may need time to acclimate yourself.

[Anonymous No.15025424]

>>15025369
>So people say suicide is selfish, would a good counter argument be that it is also selfish to forcibly bring a person into this world?
No, you're just going "aha but you also do selfish thing". Two wrongs don't make a right and all that.
>>15025396
That's not a good counter since it has no convincing power.

[Anonymous No.15025492]

What the hell are Bayesian statistics?
Explain it like I am five

[Anonymous No.15025541]

>>15025369
Is it selfish for objects to fall to the ground? the answer is irrelevant because an object would continue to fall to the ground regardless of whether we think it's selfish or not.
Similarly when one attempts suicide it is irrelevant whether they think it is selfish or not because the conditions which lead them to suicide are unaffected by it and so they would attempt suicide regardless if they are convinced if it is selfish or not (otherwise they may not be serious about suicide in the first place).

If you want to stop people from committing suicide you must identify the underlying causes, most of these can be traced to traumatic events in someones life, identifying these events and learning how to accept and cope with them is the solution, screaming "it's selfish!" at a suicidal person is useless and won't stop them, it's almost as impotent as telling a drug addict that it's selfish to do drugs, in fact in this case they are probably already convinced it's selfish but they do it anyway because they can't help it.

[Anonymous No.15025764]

Could someone recommend a book on relativistic quantum chemistry?

[Anonymous No.15026281]

>>15025492
https://youtu.be/K_pvXShHhJI

[Anonymous No.15026289]

Sorry guys, I'm a bit slow sometimes. Can someone explain kinetic time dilation in simple terms. I understand that going fast makes time slow down compared to a "stationary" observer. But I thought velocity was relative? How can there be a stationary observer? Wouldn't both observers be moving from the other's perspective? Therefore time would pass slowly for both? But that doesn't make any sense. Please help.

[Anonymous No.15026299]

>>15022799
Is this the post maid anon got banned for? How is this any different from his usual gibberish? Did he get banned for calling Schönfinkel "Flugelhorn"?

[Anonymous No.15026311]

>>15026289
You are pretty much correct. Going fast makes time slow down FROM THE POINT OF VIEW of a "stationary" observer. When you sit on Earth and watch people on a rocket passing by, they will look slowed down. The people on the rocket will see everything normal around them, and when they look down they will see you on Earth acting in slow motion. Time does not slow down in some "objective" sense for either of you because there is nothing to compare to, that is the point of relativity.

[Anonymous No.15026340]

>>15025168
I don't know of a way to get a good grasp on stats without also knowing (basic) maths. Is there a reason you expect reading textbooks to go poorly? If you can't understand one, read a textbook on its prereqs

[Anonymous No.15026345]

>>15026311
But I thought people aged more slowly on the space station because they are moving very fast?! How can they age slowly if time slows down the same on Earth and at the ISP?

[Anonymous No.15026399]

How do I approach problem 9? I understand that the greatest integer function itself is now being used as an input for itself but I don't understand how to simplify the resulting expression.

For example, I get how to simplify expressions with absolute values by using the definition and there are some shortcut theorems too. But, in this case, I'm kind of lost as to what information I'd need related to the greatest integer function in order to simplify the expression.

Or maybe I'm just missing some basic algebraic manipulation?

[Anonymous No.15026417]

>>15026345
Very good point. There is a difference between the people on the space station and the Earth ; the situation is actually not completely symmetric. What we said is true for inertial frames, ones where there is no acceleration. At the end of the stay astronauts come back to Earth. It is not the Earth that comes back to them, because they get in a rocket and ACCELERATE back to our planet. They are no longer in an inertial frame. So you can think that in the end both the astronauts and us who stayed end up together in what was the "Earth perspective". Until they are back, there is no meaningful way to compare ages, but once they use the acceleration to come back down, everyone agrees on the same frame of reference, in a way.

There are other ways to explain this, but the fact that only one frame accelerates probably makes most sense. Maybe the wikipedia article on the Twin Paradox helps ?

[Anonymous No.15026438]

>>15026399
You can take integer addition/subtraction outside the floor/greatest integer function. Also, once there are only integers inside it, writing the floor is not necessary. So you can eliminate the outside floor. In the end we get [math] 5 \lfloor 5x \rfloor - 4 [/math].

[Anonymous No.15026449]

>>15026438
I see what you're saying with taking the integer addition/subtraction outside the function but the book's answer ended with subtracting 12 instead of 4.
Is it correct to distribute like pic related to get the book's solution or is it wrong? I was under the assumption when plugging in the function, the 5 would have had to been distributed entirely.

[Anonymous No.15026455]

>>15026449
Apologies for the huge image and the text is Velleman's Calculus for reference

[Anonymous No.15026458]

>>15026449
>>15026455
You are absolutely correct, oops !

[Anonymous No.15026479]

by the spectral theorem is it correct to say that a matric is orthogonal if and only if it's symmetric? (I mean all symmetrical matrices are orthogonal and all orthogonal matrices are symmetrical)

[Anonymous No.15026487]

>>15026479
No, do a rotation around the origin :
[eqn]
\begin{bmatrix}
\cos \theta & -\sin \theta \\
\sin \theta & \cos \theta \\
\end{bmatrix}
[/eqn]
This is orthogonal, but not symmetric. The matrix [0] is symmetric, but not orthogonal.

[Anonymous No.15026513]

>>15026487
Alright, but at least it's true that a matrix is symmetrical if and only if you can orthogonally diagonalize it?

[Anonymous No.15026550]

>>15026513
Yes. A square matrix A is orthogonally diagonalizable if its eigenvectors are orthogonal. This is true if it is symmetric. If it is orthogonally diagonalizable, it can be written as [math] A = ODO^T [/math]. This means [math] A = A^T [/math].

[Anonymous No.15026569]

>>15026550
>>15026513
>>15026487
if you guys are already on the subject of linear algebra, do you guys know a good source to refresh my memory? ive taken a course two years ago and i need that knowledge now.

i need a source that is summarized, has examples and illustrations. basically a linear algebra speedrun.

[Anonymous No.15026631]

>>15026569
I have not worked through either, but maybe Qingwen Hu, Concise Introduction to LA or Schaum's Outline ?

[Anonymous No.15026633]

>>15026569
>summarized, has examples and illustrations. basically a linear algebra speedrun.
This is contradictory. I think what you want is a book that holds your hand but you are too insecure to admit it.

[Anonymous No.15026637]

>>15026399
>But, in this case, I'm kind of lost as to what information I'd need related to the greatest integer function in order to simplify the expression.
That exercise is there for you to discover properties of floor function yourself, not to ask strangers on the internet.

[Anonymous No.15026778]

Is RF sent through a yagi (or similar) antenna the same as a laser? It's monochromatic, coherent, and technically light, so aren't the the same?

[Anonymous No.15026795]

>>15026778
>technically light
no it isn't, they're both EM waves, but the frequencies are very different and that changes a lot of things

[Anonymous No.15026815]

>>15026637
So it would have been better if I had made an attempt at guessing some of those properties and then checking?
I'm unfamiliar with implied stuff like that in a math text.

[Anonymous No.15026965]

>>15026795
you sure you know what you're talking about? light is light. What exactly changes?

[Anonymous No.15026971]

>>15026965
anon probably means visible light. radio and light are part of the EM spectrum but limited to a specific frequency range.

[Anonymous No.15026983]

I've taken up the habit of practicing mental math (just four basic operations) with an online problem generator. Does this help the brain think mathematically?

[Anonymous No.15026994]

>>15026815
You can prove things in math.

[Anonymous No.15027044]

>>15026994
I had Velleman's text on proving things as well. How bad do you think it would be to skip straight to proof writing strategies as opposed to going through the typical sequence of learning sets, quantifiers, and other stuff like that?

[Anonymous No.15027101]

how do i approximate bessel functions at the origin
a bunch of different sources are giving me a bunch of different expansion methods

[i know this is a really extremely low quality post, but.. No.15027233]

anonymous responsibility and freedom of economy:

the nirvana state of self. no responsibility, complete freedom.

frontal lobe activation in planning to execute qualitative posts.

freedom thus in the superego striatal selective process.

freedom of striatal projection and switch with ego.

no accountability: dominant frontal lobe.

max responsibility threshold; sensitive;

masochism of perceptive execution?

striatal not involved/superego compliant.

critiqueless. non-dual superego. to be anonymous and critically credible, sadism
of credibility. accountability to one's worth freely, responsible to one's sensitivity
in an organized fashion critically. superego-ego finesse and coordination: freedom
without gambling and incentive, simple human state of non-self. nirvana of
anonymous humanity. atrocity in extinguished humanity? sadism in moderation. i see that.
controlled demolition, destruction and constructive chaos; the meme machine. a chorus of curiousity.

as compared to the mandated incentives of meta. normal non-nirvana configuration.
transcendent in morality with unbalanced merit earned as a collection
of qualitative virtues. promoting war and cold isolated frames of humanity
in the egoistic sense. the transcendent judgment coming from ego with thresholded
virtues. morality above as below. blackmail and incentive to gamble, cheat,
steal, lie, and murder. a flawed system that needs a higher chain of command to fix
executed by it's implementation of the consumer. consumer executing command to
gamble. false virtue and morality. a system of checks to oppress the poor or weak.
a megalith of unfathomable atrocity unchecked in war torn countries, not held responsible,
no punishment due. the body that harms itself. superego compliant. promoter of
disinformation, critical error, idealistic antisociality of narcissistic tendencies
of the global populace with clandestine or high threshold towards sadistic probabilities.
a broken system that will stab at flawed
1/2

[i know this is a really extremely low quality post, but.. No.15027236]

>>15027233
human situations or guiltless perceptions
of behavior and not hold itself accountable. executive disarray and out of control
ego to ego promotion at the expense of superego ideals and moral discomforts
as well as principles of constraint, regardless of virtue spectrums. there
is a karen. there is a blue snowflake. neither one likes you. all hate you.
there is only association by guilt.
2/2
posting pasta. hopefully this is allowed.

[Anonymous No.15027261]

>>15027101
can you elaborate? what's wrong with just using these:
https://en.wikipedia.org/wiki/Bessel_function#Asymptotic_forms
if you have multiple expressions try evaluating them numerically for values that are of interest to you to compare?

[Anonymous No.15027295]

>>15027261
I'm actually trying to approximate at exactly 0 (is that even possible?) and many methods so far will obviously end up with divide by zero. those that don't are wildly different from each other and it makes me question their validity

[Anonymous No.15027303]

>>15027044
You cannot learn prove writing strategies without those, and even if you have learnt those, you have to start with a more basic subject like proof based arithmetic, theory of equations, inequalities, etc., not calculus.

[Anonymous No.15027324]

>>15027295
>For integer or positiveα, Bessel functions of the first kind are finite at the origin (x = 0); while for negative non-integerα, Bessel functions of the first kind diverge as x approaches zero.
When it doesn't diverge it's always 0, except [math]J_0(0) = 1[/math] I think (Wolfram Alpha and a post on SE agree): https://math.stackexchange.com/questions/798561
Second kind will always be a singularity at 0

[Anonymous No.15027358]

could electricity emitted from headphones put a person into a specific 'moving' position? like a police tazer, but much more gentle? technically i mean ...

second question:
does classical conditioning according to pavlovs dogs principles on a human being actually work? is monkey see monkey do already brainwashing, /sci/?

[Anonymous No.15027387]

>>15027324
>second kind is always a singularity
FUCK
guess I'll do 0.0001 or something l0l

[Anonymous No.15027618]

>>15025541
yeah that is much better approach, thanks

>>15025396
I dont understand how its altruistic. You are bringing a child into this world to satisfy a biological need. Its especially worse if you dont have the proper resources to take care and nurture the child properly. Some countries also see children as an economic asset since they can help around a farm etc

[Anonymous No.15027717]

>>15027387
why
it should be a big negative number since it goes to minus infinity
look at a damn graph instead of staring at power series (the devil's scribbles)

[Anonymous No.15027829]

i stabbed myself with a rusty paint scraper yesterday, was deep enough of a wound to draw blood for several minutes. i'm a little concerned that i may contract tetanus as i haven't had the tetanus vaccine in 14 years, should i go see a doctor? i haven't had a checkup in ages so i'm a little concerned how they go & their prices. (im in freedom land)

[Anonymous No.15027972]

You need to eat a lot in order to increase or speed up your recovery time while sick. But while you're sick, that sickness makes your appetite feels like shit. If my body want me to recover fast, why do that? It's likr paradox.

[Anonymous No.15027996]

>>15027972
to measure your abilities

[Anonymous No.15028139]

Trying to into matrices and can't find solutions to Herstein & Winter's textbook
This question 10 in particular- I'm having difficulties certifying my answer for.
>If C is 0 and A is invertible, prove B=C using AB=AC basically
>assuming B here = 1/A
is my problem misinterpreting what B is ?

Sorry for brainlet tier question, math language really fucks with me sometimes

[Anonymous No.15028145]

>>15028139
Forgot pic
F

[Anonymous No.15028177]

>>15028139
Yes you are confused.
The C = 0 assumption is only supposed to be made in the first sentence of the question. B is also not 1/A.

[Anonymous No.15028182]

>>15028145
The first part is the special case where B=0.
It's pretty much a trivial problem just multiply with A^(-1) from the right direction.

[Anonymous No.15028195]

>>15028177
>>15028182
I see now thanks so much for clarifying

[Anonymous No.15028219]

can I still go to heaven if I kill myself?

[Anonymous No.15028279]

>>15028219
yes, but don't.

[Anonymous No.15028287]

>>15028219
hf yo

[Anonymous No.15028290]

>>15028219
why not olympus tho

[Anonymous No.15028292]

>>15017870
What was the name of that shirtless schizo that used to post some schizo philosophy here and killed himself?

[Anonymous No.15028299]

>>15028287
>>15028290
this all seems rather convoluted and unrelated to my question
>>15028279
why not?

[Anonymous No.15028305]

>>15028299
>unrelated to my question
>he doesn't understand

[Anonymous No.15028306]

>>15028292
mario montano

[Anonymous No.15028309]

>>15028305
I don't.

[Anonymous No.15028310]

>>15028305
>chainsawman
Isn't there a containment board for you?

[Anonymous No.15028334]

>>15028309
you're on /sci/, basically the rule is that energy and matter can not be destroyed or created, just converted. so once you die all your particles, of your body and even the energy of your thoughts have to be converted as you rot away.

so, where will those particles and waves and that energy and up?

you asked if it was possible to go to the (assuming here) christian heaven if you end your life out of your own accord and the answer is, yes it's possible, but i can't guarantee that to you if you kill yourself. the bible dictates that suicide is murder and you would end up in hell. but it's still possible from a scientific point of view that that is incorrect and the 'christian heaven' is just another galaxy where your particles will reassemble, so from a scientific, not religious point of view, yes, it's possible that you end up in heaven if you kill yourself. but why risk it?

you asked if it's possible. logic dictates that it is, faith dictates that it's not. physics guarantees that the chance of ending up in both heaven and/or hell, even at the same time has a possibility of higher than 0%, which in an endless universe is a gurantee that you will end up in both heaven and hell no matter what you do.
why risk it from a religious point of view?

>>15028310
i'm on my containment website
it'S an anime website

[Anonymous No.15028340]

>>15028292
i think he was called two way wiretaps of prism the third

[Anonymous No.15028349]

sup /sci/
doesn't actio = reactio forbid the possibility of free will no matter how long the actio = ractio chain is? even if it's a net of actio = reactio?
pls respond

[Anonymous No.15028354]

>>15028349
Free will doesn't exist either way. Hope that helps

[Anonymous No.15028361]

>>15028354
i hate that

[Anonymous No.15028384]

I don't understand the solution to part C. Can someone explain?

[Anonymous No.15028386]

Forgot the image

[Anonymous No.15028403]

>>15028386
Nevermind. I think I got it

[Anonymous No.15028451]

what particle properties does light have because it seems 99% wavy interactions

[Anonymous No.15028745]

>>15028451
> The photoelectric effect.
> The spectrum of black-body radiation.
> Low intensity laser beams.

[Anonymous No.15028818]

>>15028219
Thou shalt not kill.

To give a more abstract and less rules-autism (but weaker) explanation, God is the God of the living (Mark 12:27), and God's gift is eternal life freely given, but the wages of sin are death (Romans 6:23), so removing yourself from life is removing yourself from God's domain.

[Anonymous No.15028831]

>>15028818
This is a science board, take it to /x/

[Anonymous No.15028857]

What's an analysis book that has as many great and challenging problems as Lang's Algebra?

[Anonymous No.15029054]

What causes some people to be more sensitive to smells than others?
The smell of milk that's just a bit spoiler or food that's gone rancid for maybe half a day will make me gag uncontrollably and it takes a lot of effort to not vomit. I walked past some puke on the sidewalk yesterday and started gagging. I spilled some Pine-Sol today and despite being a cleaning product, the strong smell made me have a fit of gagging.
I can eat pretty much anything and my stomach will hold, but my nose is just so weak.

[Anonymous No.15029083]

>>15029054
It's genetics and calledhyperosmia, or 'super smellers'. Similar to super tasters. They are actually in demand in the food and wine industry for Q/A and testing.

[Anonymous No.15029170]

if n is 0 or 1 does this series just become 0?

[Anonymous No.15029173]

>>15029170
if n=0 then the sum equals to 0 by convention
if n=1 then it equals to the first term

[Anonymous No.15029189]

>>15029173
thank you

[Anonymous No.15029198]

how the fuck do I find the factorial of a negative number

[Anonymous No.15029202]

>>15029198
doesn't exist

[Anonymous No.15029214]

>>15029202
what the fuck
how am I supposed to do my homework then
I fucking hate analysis

[Anonymous No.15029220]

>>15029198
Use the gamma function as an extension of factorials to complex numbers.

[Anonymous No.15029223]

>>15029220
I tried that earlier and got negative infinity

[Anonymous No.15029225]

>>15029223
Yes, that's the answer.

[Anonymous No.15029229]

>>15029225
this math shit aint bussin

[Anonymous No.15029381]

Can some exokapin why when taking the derivative the numerators for the first two terms are 10x and 6. Is he multiplying by both the 5 and the 3 and then also by the derivativres of the inside function, so 5 * 2x and 3 times 2

If so why?

[Anonymous No.15029416]

>>15029381
> Is he multiplying by both the 5 and the 3 and then also by the derivativres of the inside function
Yes. It's just the chain rule, the derivative of a.f(x) = a.f'(x) +0.f(x) = a.f'(x)

[Anonymous No.15029454]

>>15029198
Also it's only infinity for negative integers, other negative numbers are fine.

[Anonymous No.15029463]

let [math]p_1 , ..., p_r[/math] be polynomials such that [math]gcd(p_i, p_j) = 1[/math] whenever i and j differ. let [math]q_i = \prod_{j \ne i} p_j[/math]. why must [math]gcd(q_1 , ..., q_r) = 1[/math]?

[Anonymous No.15029475]

>>15029463
Express the polynomials according to their roots.

[Anonymous No.15029490]

>>15029463
Polynomial rings are UFDs, which means that [math]p | ab \implies p | a \lor p | b[/math]

[Anonymous No.15029514]

>>15029416
so wait the derivative of ln( x) is actually 1/x * 1 you just dont show the 1? so the derivative of ln(2x) is 1/2x * 2 = 2/2x = 1/x? Weird I could have sworn it was just 1/2x

[Anonymous No.15029606]

>>15029514
Yes but that's just the rule for taking the derivative of ln( f(x) ) = f'(x) / f(x)

[Anonymous No.15029615]

I'm new to proofs, and looking at a few on proofwiki seems to imply there's some sort of hierarchy to them. For example
https://proofwiki.org/wiki/B%C3%A9zout%27s_Identity/Proof_5#Proof
Does this exist?

[Anonymous No.15029618]

I don't get how Stoke's Theorem is a generalization of the 2nd FTC, we go from talking about areas under curves to vector fields to the forbidden t***** fields instead of... areas under surfaces, which is what I'd expect.

[Anonymous No.15029619]

>>15029615
What are you even asking? The entire field of Mathematics is simply proofs built upon proofs based on a set of axioms.

[Anonymous No.15029633]

>>15029619
That's the intent. Start from axioms, get a proof or two, then get another proof that relies on a prior proof, and so on. I'm looking for that graph.

[Anonymous No.15029644]

>>15029633
afaik something like that doesn't exist. There are other sites like proofwiki but just as limited.

[Anonymous No.15029733]

What's the correct way to make my neural net model ignore certain pixels of an image? I want to feed in the whole image but e.g ignore the top half. I was thinking just zeroing the top half out but I'm not sure if that will bring in unwatned side-effects.

[Anonymous No.15029740]

For finding the volume of an area using revolution
why does my professor use x^4 and not x^2

And what reason does he set everything equal to y^2 and not y in this example. What if the two y values are y^3 and y^5 then what do I set y to

[Anonymous No.15029745]

is there a good way to calculate?
[math] a^{k^{l}} \equiv 1 \mod n[/math]

like it's the case with:
[math] (a^{k})^{l} \equiv 1 \mod n[/math]

I'm not asking about the relation between the two expressions but rather if there was a convenient way to simplify the first expression

[Anonymous No.15029748]

Pedophilic anime porn is illegal in the USA
>>>/news/1119430

[Anonymous No.15029767]

>>15029748
>Court documents showed that Ostrander is a registered sex offender, who was previously convicted of possession of child pornography on October 18, 2017, Lastinger said.
Do you have any evidence that it was hentai and not child pornography generated by a stable diffusion model fed children pornography?

[Anonymous No.15029786]

>>15029745
[math]a^k \mod n[/math] either eventually loops or stops at 0.

[Anonymous No.15029819]

>>15029733
In that specific case just crop the image. In general create a zero mask for the pixels you want to ignore and multiply it by your first layer.

[Anonymous No.15030021]

https://music.youtube.com/watch?v=OXWwiYeXqE0&feature=share

what does sport mean in german? spott as in humilation or sport as in sports? /lit/ was no help need linguists, might be a new slang variant on the german word for sports...
according to petrovich petrovsky language can evolve into anything

[Anonymous No.15030034]

>>15029767
my failsafe artificial intelligence just told me it was japanese handrawn art, not american live action

[Anonymous No.15030038]

>>15029740
can someone answer me

[Anonymous No.15030043]

>>15030038
set y to f(x)=dx and you should be able to solve the riddle

[Anonymous No.15030047]

/sci/ who invented .gif (dot give)?

[Anonymous No.15030054]

/sci/ who inveted rust and .mp3?

/sci/ how does a phone booth work?

/sci/ what happens if you feed data via nonexecutable to a custom interpreter, like an executable?

/sci/ since when can cigarettes talk when you twirl them?

/sci/ whut's naano tech?

/sci/ whuats bio nanotech?

/sci/ how doehs xiomis transparent display werk?

/sci/ whut is internet of things?

/sci/ wats an autopen??

[Anonymous No.15030056]

>>15030043
Well I figured I just need to take whatever is being done to the second y in this case squaring it and then apply that to the function that is not y^2

So if it had been y=x^2, y^3 = 8x,
then it would be 8x-x^5 right?

I don't understand your instructions though I thought y and f(x) were the same thing and the derivative of what?

[Anonymous No.15030061]

>>15030043
What about here why is here getting the square root of all the terms in the antiderivative

https://www.youtube.com/watch?v=D5sT1br9soI
I'm trying to understand through watching this video but the problems are formatted slightly differently

[Anonymous No.15030068]

Can someone explain the difference in these two methods one being my professor and the other being organicchemtutor

>>15029740
proffesor

My professor seems to seems to combine the two functions given and then factor, the organic chem guy doesn't do that. And in this picture where does organic chem guy get the x value from in R = x

[Anonymous No.15030141]

How important logarithms of negative numbers? Technically they shouldn't exist but the result is an imaginary number. Is that used anywhere?

[Anonymous No.15030242]

Any recommended math graphing software? I just want to input 3d functions and get familiar with the shapes quick. Preferably free and does not require learning a quasi programming language. Scientific Workplace is perfect but it doesn't seem to work without a license that they do not sell anymore

[Anonymous No.15030300]

Is this a valid proof?

Let XUY = X for any X. Prove Y = [math]\emptyset [/math]
Suppose to the contrary that Y [math] \neq \emptyset [/math]. Define X such that X [math] \cap [/math] Y = [math] \emptyset [/math]. Then [math] (\exists x)(x \in Y) \Rightarrow a \in Y \Rightarrow a \in X \cup Y \Rightarrow a \in X \ (sub). \\ Then \ a \in X \wedge a \in Y \Rightarrow a \in X\cap Y \ \Rightarrow (\exists x)(x \in X\cap Y) \Rightarrow X\cap Y \neq \emptyset. \\ A \ contradiction. [/math]

[Anonymous No.15030324]

>>15030300
Yes

[Anonymous No.15030328]

Can ChatGPT answer all of these questions and explain things to me like I am 5? Is it the future?

[Anonymous No.15030335]

Why does egg-based sauce tend to cool faster? Any chemfag can explain this?

[Anonymous No.15030404]

What's a good drawing tablet if I'm just going to use it for equations and diagrams?

[Anonymous No.15030423]

How do i prove the open interval (0,1) is infinite? (Not proving uncountable, just infinite)

[Anonymous No.15030446]

>>15030423
Find an injection from a set known to be infinite into (0,1).

[Anonymous No.15030452]

>>15030300
>Define X such that [math] X \cap Y = \emptyset [/math].
This is a bit hand wavy, you need to give a more explicit definition for X, something like "Define [math] X = A \setminus Y [/math] Where A is any set." or more simply "Define [math] X = \emptyset [/math]."
The rest of the proof seems valid though.

There's actually a much easier proof, since [math] X \cup Y = X [/math] is true for any X then it's also true when [math] X = \emptyset [/math], so
[math] \emptyset = X = X \cup Y = \emptyset \cup Y = Y [/math]

[Anonymous No.15030466]

>>15030446
ty i'm having a lot of trouble with proving infinite sets.

i tried defining a set (0, 0.1) and a function from (0, 0.1) to (0, 1) where f(x) = x+0.1, but then i realised i cant prove it is a surjection and i think it needs to be a bijection.

then i tried defining the set of Q of rational numbers a/b where a is greater than 0 and less than b (so that a/b is between 0 and 1), but i dont know how to make a function from Q to (0,1) that is a bijection.

i appreciate any help you can give because i cant find anything online for proving (0,1) is infinite, just uncountable.

>>15030452
that's very clever and thank you for how to make a more explicit definition.

Is the empty set genrally a good starting point for problems that say "for any set"?

[Anonymous No.15030495]

>>15030404
iPad Air

[Anonymous No.15030498]

>>15030404
gaomon M10K, buuuut i think you have to use an older driver for the touch wheel to work properly on windows :)

[Anonymous No.15030500]

>>15029633
It's called a textbook

[Anonymous No.15030569]

im doing a physics 2 lab about resistivity... it says to graph voltage vs length, does that mean that voltage is on the x or y axis?

[Anonymous No.15030601]

>>15030569
how are you in physics 2 lab and you don't know what independent vs dependent variables are, anon. The y axis gets the response variable. I'm assuming you're measuring the voltage as it "responds" to your application of different lengths or whatever.

[Anonymous No.15030613]

>>15030601
okay i looked the graph up and most of them are the length on the x axis and the voltage on the y axis. what you said doesnt make sense because both of them change

i cheated my physics and math classes online so now im doing in person labs and i dont know anything and neither do the other students and the professor with a fancy phd who thinks they're hot shit just tells us to hand in the labs and we''ll get a C

[Anonymous No.15030620]

I was supposed to find the domain of the function and write the answer as a union of intervals.

I can simplify this down to:
(4-x)(4+x)/2-x
I get the idea that the domain is implied to be whatever makes sense from the set of real numbers.
The domain shouldn't include 2, and the input to the function shouldn't cause whatever is under the radical to evaluate to something negative.

So I tried creating the inequality of:
(4-x)(4+x)/2-x >= 0
But I don't really understand the results I got.
Depending on how I manipulated the inequality, it came out to either:
x >= -4
or
x <= 4

I thought the answer was a union of [-4,2) (2,4]
but the book's answer was the union of [-4,2) [4, infinity)

This is where I'm lost as to whether my approach is wrong or I'm missing information to make sense of what I was doing.

[Anonymous No.15030690]

>>15030620
theres two disjunctions in this problem, square root of a negative number and dividing by zero. if x = 2 you divide by zero. if the top/bottom = negative you take the sqrt of a negative number. if I plug in 3 (included in the set for your answer) I get sqrt(7/-1) which is not allowed. If I plug in 5 I get sqrt(-9/-3) which is fine

[Anonymous No.15030698]

Help with p=1

[Anonymous No.15030712]

yo /sci/ when i rub my fineliner and it starts talking to me very faintly, is it a bluetooth enabled internet of things pen or do i have schizophrenia?

[Anonymous No.15030713]

trying to simulate ideal Rankine cycle with multiple reheats and the prompt suggests constant pressure ratios between each turbine stage instead of just partitioning the difference between the boiler and condenser pressures into equal pieces.
is this normal? why would this be done?

[Anonymous No.15030726]

>>15030690
Okay, so am I expected to reason through finding the domain in the way you explained solely, or is there an explicit procedure/algorithm that would have just gotten me the answer I mentioned previously?
It feels like it's easy for me to make a careless mistake and leave possible domain elements out by just reasoning but if it's just a matter of practice I can deal with that.

[Anonymous No.15030729]

assume the mixed box in bertrand's box paradox has N golden and N silver balls, why does increasing N converges the paradox's chance of drawing a second golden ball to 5/6?

[Anonymous No.15030743]

Is the mathematics of our universe only true in our universe, or is it also true in other universes?
Would another universe have completely different mathematical laws that govern it?

[Anonymous No.15030755]

>>15030743
If all is material and mathematics is based on the material, then a different material should result in different mathematics. Id even say there could be a universe where mathematics couldnt exist, not that any human here would be able to imagine such a thing

[Anonymous No.15030756]

>>15030466
I would use N. Find some function that sends every natural number to a number equal to or smaller than 1. You can also use an infinite subset of N, like even numbers or numbers bigger than 5.

[Anonymous No.15030776]

>>15030466
uncountable means, in a loose sense, that no matter how you try to map the natural numbers to the set, there will always be numbers in the set that aren't mapped to.

a function f from (0,0.1) to (0,1) defined by f(x) = x+0.1 is not a bijection.
a function f from (0,0.1) to (0,1) defined by f(x) = 10x is a bijection however. showing that it is a bijection proves that both the sets have the same cardinality.

to show that it is a bijection, show it is injective and surjective. a mapping is injective iff f(x) = f(y) => x = y, or equivalently, x != y => f(x) != f(y).
wlog then let y>x. then by f is strictly increasing, f(y)>f(x) follows immediately. it is strictly increasing because 10(y-x) > 0 when y>x (y-x>0).
to show it is surjective, we must prove that for every element y in (0,1) there exists an x in (0,0.1) such that f(x)=y.
well take x=y/10, then f(x)=y and by 0<y<1, 0<y/10<0.1 is clearly in the required domain, and so the function is surjective.
being both injective and surjective, it is a bijection, showing that (0,0.1) and (0,1) have the same cardinality

[Anonymous No.15030822]

In a random permutation of 10 consecutive integers, all equally likely, what is the probability that the number in the 3rd position is greater than its neighbours.

[Anonymous No.15030823]

In a random permutation of first 10 consecutive positive integers, all equally likely, what is the probability that the number in the 3rd position is greater than its neighbours.

[Anonymous No.15030831]

>>15030823
fix the third position as n
then we require those to the left and the right to be less than n. there are clearly (n-1)(n-2) to do this. then permuting the remaining 7 gives

P_n = ((n-1)(n-2) * 7!) / 9!

since n = 1, 2, 3, 4, ..., 10 all occur with equal probability, the total probability is 0.1(P_1 + P_2 + ... + P_10)

note 7! / 9! = 1/72, so this is

1/720 ( (1-1)(1-2) + (2-1)(2-2) + ... + (10-1)(9-1) )

which using simple summation rules is

198 / 720

which is

11/40

1/720 (

[Anonymous No.15030835]

>>15030831
i summed it wrong, correct answer is 240/720 = 1/3

[Anonymous No.15030841]

>>15030835
after getting this answer, i realize the smart way to do it would be to consider the three numbers in position 2, 3, 4, and since of the six permutations of those only two have the one in the third position being the highest, the answer is automatically 2/6 = 1/3

[Anonymous No.15030865]

What math i need into psychics?Can u give some little book guide?

[Anonymous No.15030874]

>>15030841
How does this method consider all permutations?

[Anonymous No.15030895]

>>15030865
Addition and some basic scam tactics.

[Anonymous No.15031011]

Is the Planck constant a free parameter in the standard model? Is it based on the fine structure constant?

[Anonymous No.15031027]

>>15030874
it's pretty simple
create a bucket of 3 numbers, and a bucket of 7 numbers. choose 3 numbers (in every way possible) from the 10 to place into bucket 1, and the remaining into the bucket of 7 numbers.
then the total permutations are found by permuting each bucket. since the permutations of each bucket are disjoint from one another, we can consider the permutations of the bucket of 3, and only 2 of the 6 permutations result in the middle item being the greatest. so we are done.

[Anonymous No.15031214]

>>15031011
No and no. h is a fundamental constant. You could argue the fine structure constant isn't since it varies with energy scale.

[Anonymous No.15031226]

>>15030776
ty so much i really appreciate this insight, i will try writing up a proof like this

>>15030756
ty anon, i'm confused though cause i thought you had to find a set that was a strict subset of the one you are trying to prove is infinite?

[Anonymous No.15031242]

>>15031027
Thanks.

[Anonymous No.15031244]

A function f(x) is derivable from the left and from the right in a point C, and the two derivatives are the same. Does this mean that the function is derivable in C? Do I also need to say that the function is continuous in C or is that implied?

[Anonymous No.15031251]

>>15030865
read any book that has a title in the lines of "mathematics for engineers / physicists".

[Anonymous No.15031252]

>>15031226
That is a different possible strategy. If you can find a bijection between the set and a strict subset of it, that means that the set and subset are "the same size". This is not possible unless the set is infinite.

But another option is to find an injective (one-to-one) mapping from an infinite set to the set you are trying to prove. For example, 1/N for all N (skipping 1) gives different reals in (0,1). This means that N "fits inside" your set, and since N is infinite, your set is also infinite.

[Anonymous No.15031268]

Why would a flying craft that is essentially a giant electromagnet not work?

[Anonymous No.15031269]

>>15031244
Showing its differentiable from both sides suffices.

[Anonymous No.15031291]

Isn't time dilation a load of shit when it comes to your biological clock?
Your body will age 6 years in the same time another body ages 6 years regardless of where you're at in space?

[Anonymous No.15031312]

>>15031268
magnetic levitation already exists, the problem is the absurd amount of power you'd need
>>15030404
pen and paper zoomer

[Anonymous No.15031332]

>>15019947
At the same speed, it would need to add force to keep it going against resistance.

[Anonymous No.15031346]

>>15031268
how will you contain the absurd amounts of leakage flux?

[Anonymous No.15031361]

>>15030698
If X<Y a.s. then EX<EY, a contradiction

[Anonymous No.15031432]

>>15031291
None of that is true.

[Anonymous No.15031529]

>>15030726
you should just look and see when the top and bottom are both + and - and compare, plus any disjunctions like dividing by 0

[Anonymous No.15031668]

>>15031432
Dude, be specific, you pretentious fuck.

[Anonymous No.15031669]

>>15030874
>>15030841
Can't you just say there's 3 positions you're considering so by symmetry it's trivially 1/3 if you aren't considering repeating digits?

[Anonymous No.15031752]

>>15031668
Specifically everything the anon wrote in their post is wrong.

[Anonymous No.15031808]

>>15030743
Mathematics are equally true everywhere, since it's truth derived a priori from a set of statements (axioms) and has no relation whatsoever to physical reality.

[Anonymous No.15031846]

How do I solve this faggot? It's right next to several trivial limits, but I can't figure it out.
I figure I should probably split it into a few functions based on addition and then use approximations of ln but it doesn't really work out except that I get a 0 for the 3x one.

[Anonymous No.15031885]

>>15031846
L'hospital this shit

[Anonymous No.15031891]

>>15031885
Can't use L'hospital yet.

[Anonymous No.15031959]

>>15031846
>>15031891
Take the first term of the taylor series for each trig functions and ln.

[math]\dfrac{\sin{2x} + 2\tan^{-1}{3x} + 3x^2}{\ln(1 + 3x + \sin^{2}{x}) + xe^x} \implies \dfrac{2x + 6x + 3x^2}{3x + x^2 + xe^x}[/math]

Hopefully you know how to take that limit.

[Anonymous No.15031984]

>>15031808
Certain axioms are false though. Like in Set Theory, there is one axiom says that if you
take just some of the elements of a set together, then they also make a set.
But this is not true in poker; every set is three cards and no less.

[Anonymous No.15032226]

>>15031252
oh okay tyvm anon i appreciate it

can you tell me why this function is used to prove R is infinite?

its a function from (0,1) to R, such that f(x) = (2x-1)/2 if 0<x<=1/2, and (2x-1)/(1-x) if 1/2<x<1

it seems so complicated i don't understand why this function was used

[Anonymous No.15032237]

>>15032226
(2x-1)/x if 0<x<=1/2 sorry

[Anonymous No.15032483]

What majors should I consider if I want to study the process of learning from both the biological and computational perspective?

I'm currently studying computer engineering. But I'm mostly interested in ai, neuromorphic computing and synthetic biological intelligence. Would a double major in CE and biology (or bioinformatics) be a good choice?

I'm currently at a community college so I could knock out both associates very cheaply, but I'm also worried this would be a waste of time? Though, I'm in it for the long run.

[Anonymous No.15032535]

>>15032483
If you wanna learn about the process of learning, you don't really need to know a lot about biology. Most of the stuff written out there about pedagogy is written from a psychological or philosophical perspective, which means that it will rarely touch upon the actual physical/chemical mechanisms involved in the process.
Even though nowadays we got CRT scans and tons of other tools to measure electrical signals in the brain, the way "neuroscientists" describe the brain is still on a very abstract level, like some kind of sponge capable of picking up knowledge from concrete phenomena that are arbitrarily linked together through organizational thought-concepts.

[Anonymous No.15032637]

>>15032535
>If you wanna learn about the process of learning, you don't really need to know a lot about biology.
Your probably right for the majority of cases. But I guess I'm specifically interested in studying some cases where knowledge of biology (or neuroscience?) overlaps with computing, for instance with 'in-silico' neural networks.

Although, maybe I should also read up on the psychological and philosophical perspectives, like you mentioned. I've heard allot 'Thinking Fast and Slow' so I may read that.

[Anonymous No.15032651]

I believe the system is predator (N2) and prey (N1) interaction, but I'm not sure how to solve the second half of the problem.

Can someone show me where to start? I'd like to try to do it without nondimensionalizing it if possible.

[Anonymous No.15032726]

>>15032226
That is the first method, finding a bijection between a set and its subset. We want a bijection between (0,1) and R.

The first problem is that (0,1) covers a small range ; it fits between two integers. We want to expand it to be infinitely wide. The first thing I would think is use 1/x. Since x < 1, this will go up to infinity. This is a bijection between (0,1) and (1,infinity). It's a start.

A problem is that (0,1) is completely positive, but if we want a bijection, we need a way to also get all of the negative numbers. A logical way to do this might be to find a function that expands (0,1) symmetrically, so that the left half of the interval (0,1) corresponds to the left half of R and the same thing on the right. Basically, a bijection between (0,0.5] and R-, then another between [0.5,1) and R+. You can visualise stretching (0,1) over all of R with the middle of the interval landing on 0.

Let's start with the bijection from [0.5,1) to R+. We already mentioned 1/x. We want the denominator to approach 0, so since we limited x to [0.5,1), we can try [math]\frac{1}{1-x}[/math]. This maps to [2,infinity). How do we lower this so it reaches down to 0 ? We make the numerator approach 0. We could make the numerator x-1, so that it approaches 0 as x approaches 1. But this would give us negative numbers, which is not what we wanted. Better find something that is 0 for x = 0.5 and positive otherwise. 2x-1 works well. So we have found that [math]\frac{2x-1}{1-x}[/math] is a bijection between [0.5,1) and R+. A similar train of thought can be used for the bijection between (0,0,5] and R-. Put together, these give a bijection between (0,1) and R. So R is the same size as its subset, and thus infinite.

[Anonymous No.15032729]

>>15032226
>>15032726

The function is complicated, and it can look a bit artificial if you just see the answer, but I don't think you will find a simpler bijection between (0,1) and R. It is a good exercise to show R is infinite using a bijection with a subset, since it is a strategy that works well in general. But in practice, I would use the method with N we mentioned.

>>15030776
Or like anon said, the function 10x is a bijection between (0,0.1) and (0,1), which shows that (0,1) is infinite. Since R contains an infinite subset, it has to be infinite too.

[Anonymous No.15032789]

I need some help with proving the following properties of a stern brocot tree inductively:

1) Each element is in its reduced form.
2)Every positive rational appears at least once.
3)All elements are unique
4) If you go from left to right, the denominator of each level is the numerator of the next node's level.

[Anonymous No.15032798]

To solve this I need to be able to find the nullclines, but for some reason my brain is shitting out and I feel like I'm messing something up. I have:

F' = aF(1 - F/K) - bFN
N' = cF - dN

I feel like I'm supposed to have an extra F or N parameter for the N' equation, since otherwise i have a nullcline that includes one of the population variables (F or N), but the way the problem is worded keeps making me second guess myself. Could someone provide some assistance?

[Anonymous No.15032808]

>>15017870
If a function can't have empty range and nonempty domain, why can you define a void function with argument in C++?

[Anonymous No.15032820]

>>15032808
>>If a function can't have empty range and nonempty domain, why can you define a void function with argument in C++?
In C++, a void function is a type of function that does not return a value. This means that a void function has an empty range, just like a mathematical function with an empty range. However, unlike a mathematical function, a void function in C++ can still have a nonempty domain, meaning that it can accept input arguments.

[Anonymous No.15032828]

>>15017870
I was asking questions in my thread but it got jannied to /wsr/ for some reason. I wasn't requesting anything, but I don't think the janny who jannied my thread cares.

I am making the definition of Maid Space in code nicer by letting it have up to 255 dimensions which java spec says is maximum amount. Attached is the new definition.

It is giving me problems from "code too large" compilation error.
(cont)

[Anonymous No.15032831]

>>15032828
Problem is I want to iterate over the array to print it. This requires nesting a lot of for loops (see attachment). Is there a better way to do this than nesting 255 loops?

>use recursion
This is not possible. Java uses something called a stack to handle recursion. Java is unfortunately a stacklet with a small stack and trying to recursion over this this will cause StackOverflowError. Solution has to be iterative. I just don't know is there a better iterative solution?

[Anonymous No.15032867]

learning all of this information is interesting and all and like anyone can can just learn it but how do people come up with it in the first place? how can i think about something new and make some discovery?

[Anonymous No.15032873]

>>15032808
Because most programming languages (including C++) use "function" to mean "procedure". A procedure's inputs aren't limited to its parameters, and its outputs aren't limited to its result.

In a functional language (where functions are actual functions), a function which returns no result (typically meaning that the result type is a 0-tuple aka unit) is usually allowed but would be pointless.

[Anonymous No.15032883]

>>15032828
>up to 255 dimensions
Pointless. A dimension of size 1 is redundant. And if you have 255 dimensions all of size at least 2, then the total number of elements will be at least 2^255 which isn't addressable on a 64-bit system and wouldn't fit into the combined memory of every computer on Earth.

Also: recursion shouldn't be a problem. Unless most dimensions are of size 1, you'll run out of memory before you run out of stack. You can control the stack size with the -Xss command-line switch to the JVM.

[Anonymous No.15032930]

>>15032883
>Pointless. A dimension of size 1 is redundant. And if you have 255 dimensions all of size at least 2, then the total number of elements will be at least 2^255 which isn't addressable on a 64-bit system and wouldn't fit into the combined memory of every computer on Earth.
Most of them will be 0 in practice. I just want the code to support it without giving me "code too large" problems. This way a user can sort of dynamically determine the dimensions. Get a prompt. Prompt says how many dimensions? Tell it 3. It asks you sizes. For arguments, let's just say 2, 2, 2. So now the array is actually boolean[2][2][2][0][0][0][0]....[0].

>Also: recursion shouldn't be a problem. Unless most dimensions are of size 1, you'll run out of memory before you run out of stack. You can control the stack size with the -Xss command-line switch to the JVM.
Recursion is always a problem in Java. Even with adjusting stack size it is frequently too small. Last time I had this problem I was making digits for a radix 2^(16) number system. Each digit is represented as a 4x4 boolean array. I put them in a list and tried to save it to file. Java kept exploding because ObjectOutputStream is recursive and Java is a stacklet and it kept making StackOverflowErrors. Adjusting size achieved nothing except letting the program run slightly longer before StackOverflowError. I ended up having to write my own serializer which was iterative to make it work properly.

In that code Maid Space is always 2D thought and I want to allow more dimensions without creating every case by hand or using anything outside boolean array or int array. I want to do this without using tricks from Collections.

My goal is figure out how to use the powers of 255 dimension arrays for counting, which is the computer's most important task.

[Anonymous No.15032936]

I'm learning statistics on my own.
>Data that are not only made up of counting numbers, but that may include fractions, decimals, or irrational numbers, are called quantitative continuous data.
Isn't this incorrect?
Let's say I have a variable whose value can range from 0 to 20 in increments of 0.1; wouldn't that be discrete data because there are a finite number of possible values, despite "including decimals?"
Definition is from the OpenStax statistics textbook if you're curious.

[Anonymous No.15033010]

>>15032808
>If a function can't have empty range and nonempty domain
says who?

[Anonymous No.15033052]

>>15032936
This is what you get for reading OpenStax.

[Anonymous No.15033109]

>>15033052
I thought OpenStax is alright. I still think they generally are. Anyway, they're not the only book I reference. Do you recommend any specific resources for statistics and probability?
Also, you didn't directly answer my question regarding the definition of continuous data.

[Anonymous No.15033117]

what does 'the not autonomous controlled will' actually mean? need a logician or linguist here, i am unfamiliar with this saying

[Anonymous No.15033137]

>>15033109
As the name implies, it's data with values over the real numbers.

[Anonymous No.15033139]

>>15032930
>So now the array is actually boolean[2][2][2][0][0][0][0]....[0].
It would be [1][1][1]...[1][2][2][2]. The size of the array is the product of dimensions, so if any of the dimensions are 0, the array is empty.

If you wanted a practical n-dimensional array class, you'd do it like NumPy: store a list of dimensions and a 1D array which holds the data. But then you wouldn't be able to use Java's array-subscripting syntax because you can't define your own operators.

> Recursion is always a problem in Java. Even with adjusting stack size it is frequently too small.
If 1MB of stack (the default) isn't enough for 255 dimensions, you're using more than 4k per stack frame; which is way too much. Stack overflows are usually down to someone forgetting a base case or trying to port code which relies upon tail-call optimisation (which Java doesn't do).

DESU, it sounds like you're going out of your way to trigger Java's limitations. Either use a different language or adapt (e.g. use an explicit stack with push/pop rather than recursive functions).

[Anonymous No.15033193]

>>15033109
No they aren't alright. What is this zoomer obsession with le free stuff when better pirated stuff is readily available. Continuous data is any data which can be measured with infinite accuracy (or modelled as such), hence the theory of continuous distributions can be applied to it. This typically includes any data with non integral entries, but that's not the definition. For example, similar to a probability density function, you may define a function [math] n [/math] such that:
[math] \int_a^b n(x) \mathrm dx = [/math] number of people earning income between [math] a [/math] and [math] b [/math]. This is an income density. Much continuous random variables, it makes sense to use density function instead of mass function because number of people earning the exact same income down to the lowest fraction of penny is very low.
See applications of income density function here https://www.jstor.org/stable/1913013

[Anonymous No.15033220]

>>15032936
>Let's say I have a variable whose value can range from 0 to 20 in increments of 0.1; wouldn't that be discrete data because there are a finite number of possible values, despite "including decimals?"
Not necessarily.
If you measure lengths with a ruler that has a precision of 0.1cm, your data is still continuous, it's just been truncated to 0.1cm

[Anonymous No.15033336]

I have put them in order as best as I could but Im missing something nad it's driving me nuts, can't think of anymore steps I could add

[Anonymous No.15033532]

Why is [math]\langle \emptyset\rangle = \langle e \rangle[/math]

[Anonymous No.15033656]

if [math]\bigcup\limits_{n=1}^\infty A_n[/math] denotes a countably infinite union, how is an uncountably infinite one denoted?

[Anonymous No.15033676]

>>15033656
[math]\bigcup_{i \in I} A_i [/math] where [math]I[/math] is an uncountable index set

[Anonymous No.15033708]

does anybody else ever feel too stupid for this? I genuinely like the things I study but barely pass my exams (American equivalent of a C I guess)
My friend who studies something similar who doesn't give a shit about the subjects got almost full grades on everything

[Anonymous No.15033713]

Difference between the shell method washer method

Okay so for both of them I find the points of intergration by getting x. Is there a difference in how I do this. My professor in shell example sets the functions equal to each other and then factors x.
y=x^2, y^2=8x

For the washer method he solves for x,
y=x^2, y=4-x^2

But its only different because the y values are different, if you switched the sets of y values from the washer to dish you would still find the points of intergration the same way right?


And then for the formula for washers its the antiderivative of
pi * [(r1^2)-(r^2^2)
?

And for shell method its antiderivative of
2pix * (r1-r1)
So instead of squaring r1 and r2 I multiply them by x, and its always just x right that doesn't change; its never like x^2 or 2x?

And then after that I just solve

Is all that the proper method?
I still don't really get what determines whether its r1 or r2

And when is says about the y axis or about the x axis what does that mean?, what changes in the formula

[Anonymous No.15033717]

>>15033713

[Anonymous No.15033829]

Can someone explain how to do the nondimensionalization? I don't understand how they chose those parameters and how it all adds together to make a new equation

[Anonymous No.15033990]

>>15033708
What fun would it be if it were easy? You haven't hit the ceiling yet, so just enjoy it.

[Anonymous No.15034168]

>>15032726
>>15032729
ty so much anons, i have these posts all copied and i will review them tonight while i redo the problem, i appreciate all your help!

[Anonymous No.15034227]

>>15017870
How in the fuck did the author derive:
sin(a)cos(a)-sin(b)cos(b) = tan(b - a)
??

[Anonymous No.15034281]

>>15034227
Well if you multiply out the 3rd equation you get the 2nd (remembering that sin^2 + cos^2 = 1). I can't think of an obvious way to go in the other direction though. After that just use the angle sum identities.

[Anonymous No.15034314]

Do you think biocomputers will become mainstream within our life times?

[Anonymous No.15034478]

pretty slow thread rn