/sqt/ - Stupid Questions Thread

Ask your stupid questions here.

Other urls found in this thread:

m.youtube.com/watch?v=2s4TqVAbfz4
youtube.com/watch?v=Pg_M0SsBNTA
nasa.gov/exploration/home/15mar_moonquakes.html
rapidtables.com/math/symbols/Basic_Math_Symbols.htm.
twitter.com/AnonBabble

If time is the 4th dimension, whats the 5th dimension ?

What fifth dimension?

Here's some spatial dimensions for you:

m.youtube.com/watch?v=2s4TqVAbfz4

Am confused about this q. For the centripetal acceleration, shouldn't the r used be the actual radius of the circle, not the diameter?

Either way I get a different numerical answer than the one here, same magnitude though.

(same answer for diameter, different answer for mass)

Could someone provide me a simple but nontrivial example of a clopen set, for example by using the real line or assisted by an image? I just did some introductory topology and I can distinguish open from closed easily enough but I can't quite see how it can be both at the same time, except for trivial cases like empty or the whole set.

What the fuck is discrete mathematics and why do I have to take it for my computer science degree. Also, should I take calculus before taking it? It's not a prerequisite.

it's the most epic lower-div math class that exists and there will probably be 1 or 2 sections of a semester long course that make use of the concept of a derivative, but other than that calc isn't required
(at least that's the way it was at my school)

Alright, thanks!

If it is possible to reverse the age of one cells to an earlier state would reverse aging be possible? And would it also affect the person's physical appearance and bodily organs?

Is it even possible to reverse the age of cells/alter them to be young? How expansive would this be if possible?

Why do fermions and bosons spin? What is the difference between half and integer spin?

what's some good background chatter to listen to while studying/doing research?

I usually listen to NPR in the mornings during my breakfast and stuff but would like something to listen to when i'm working on my research also. I don't really know of many podcasts; don't think i'd care for joe rogan while studying.

The awnser is clearly 7; and letters shouldnt' be used in math anyway, it just makes shit confusing.

There's a neat video on this new technique called CRISPR that uses a protein (?) in cells to identify a sequency of DNA and then another method is used to replace that sequence with one you'd like. In theory this could help with aging related genes. They could also identify cancer which replicate rampantly and possibly cure it.

Aging is directly related to the telemeres. They are in the cells and shed when your cells replicate. Eventually cell replication slows down and results in what we know as aging. Some scientists have already added telemeres to mice and they've gotten noticeably younger. Unfortunately this also caused rampant regeneration (cancer) and gave them tumors and the like.

Linking these two methods could stop cells from replicating while making people younger.

This is extremely "if this then that". I advise you to look it up yourself.

(a; b] or ]a, b] however you want to call it. Set of numbers greater than a and less than or equal to b.

Explain Googolplex.
And googol
If googol is a 1 followed by a hundred zeros shouldn't googolplex be a one followed by a thousand zeros

That's pretty interesting information. I'll try looking up that video by CRISPR.

Thank you for responding to my question user.

What ? That's not what clopen means

It's a good question because, actually, there are no nontrivial examples of clopen sets on the real line with its usual topology (it would be an excellent exercise for you to find out why).
However, *inside [0,1] U [2,3]* with the induced topology from the real line, [0,1] is a clopen set.
The idea is that a clopen set is a closed set that has an empty boundary, so it has to form a "separate part" (in a sense) from the rest.

What is that E - like symbol?

Has Anyone Really Been Far Even as Decided to Use Even Go Want to do Look More Like?

An element of
I.e the point (2,4) within the R^2 field

Thanks m8

Am I autistic? How do I prove this?

Does a master's in Chemistry actually open you up to several careers or am I getting memed on?

Try plugging in some values for x and plotting trends in your results.

Is there a way to solve this without graphing

i think his point was that by getting some visual intuition of the problem, it'll be easier to formulate a proof
(i hope)

it does but i think it's biggest benefit is offering you more time to gain research experience, allowing your CV to look more appealing to phd programs rather than how it'd look with just a bachelors.

|cos|

I get that idea, more or less, and I'm completely autistic--how do I go about proving that? The amplitude of both sin and cos cannot exceed 1, that much I understand. Sine and Cosine waves overlap and are essentially translations.

99% invisible is interesting when you listen but also well produced enough to make pleasant background noise

googolplex is 1 followed by googol zeros, it's 10^googol

>If googol is a 1 followed by a hundred zeros shouldn't googolplex be a one followed by a thousand zeros
What makes you think that? They're both just made up words given to absurdly large numbers.

giving it a listen right now.

seems great so far, thanks.

Try these, in this order on weekdays:
>Glenn Beck
>Alex Jones
>Sean Hannity
>Michael Savage
>NewsReal
>Coast to Coast AM
Those are all pretty much back to back (NewsReal's a podcast), and by the time you reach the end of this list, you'll have been awake for 20 hours. Enjoy!

:|

A few other casts to consider

>This American Life
Storytelling podcast, stories can be interesting, heartwarming, heartbreaking or anything.
>The Dollop
Two comedians, one reads about an unusual person/event to the other and they riff on it, pretty funny.
>Song Exploder
Artists dissect and talk about making a particular track of theirs.
>Kermode and Mayo's film review
Podcast of BBC 5 live show, Kermode is a film critic and Mayo is a radio presenter, films are reviewed and discussed and an actor/director is interviewed each show. Good listening even if you're not super into film, their on-air chemistry is v cosy listening.
>Hound Tall
An expert explores a deep topic with a panel of comedians who discuss and riff on it (the episode about dance music history is really good)

>Alex Jones

youtube.com/watch?v=Pg_M0SsBNTA

2D time

jokes aside, coast to coast AM as background chatter makes for a pretty cozy atmosphere. Crazy conspiracy theories while bundled up during a storm. 10/10 comfy man

would it be feasable to keep a person alive for 20 years purely by means of blood transfusion if one was limited to 1000 CE tech

Does spin on particals have units? Is it a rate or something?

Well the proof goes someting like this

Because integral in linear operator:
[eqn]\int_{-1}^1{\sin(x^3)} + {\cos(x^3)}dx = \int_{-1}^1{\sin(x^3)}dx+ \int_{-1}^1\cos(x^3) dx[/eqn]

Now because [math]sin[/math] is odd function [math]\int_{-1}^1{\sin(x^3)}dx = 0[/math] and [math]cos \leq 1[/math] we have

[math]\int_{-1}^1{\sin(x^3)} + {\cos(x^3)}dx [/math]
[math]= \int_{-1}^1{\sin(x^3)}dx+ \int_{-1}^1\cos(x^3) dx[/math]
[math]\leq 0 + \int_{-1}^1{1} dx[/math]
[math]\leq 2[/math]

As desired

What is the serious scientific explanation for why the moon rung like a bell when they crashed the Apollo lander into it?

Is it true that craters on the moon generally have a very similar depth?

>What is the serious scientific explanation for why the moon rung like a bell when they crashed the Apollo lander into it?
wut

>youtube.com/watch?v=Pg_M0SsBNTA
Nice job finding a vid that was taken completely out of context. He's not dumb, you know.

nasa.gov/exploration/home/15mar_moonquakes.html

Simile

i suck at math and most things minus politics and history but my reasoning is, is googol is 1 +100 zeros then shouldn't the next step up to get googolplex be 1+ 1000 zeros has 1000 the next step from 100, so my thinking puts it together and it makes sense, but the way it's describe that it would stretch from end to end of the galaxy makes no sense to me I mean if you can fit googol on a page why not googol plex?

Chemistry Question.

I was told that if you mix the right amount of vinegar with chlorine it turns it into weaponized class 6.2 poison.

What is the right amount/ratio of vinegar and chlorine to make this?

Well I mean chlorine is freaking dangerous. The reaction is 1 to 1 if I remember correctly.

I'm struggling with deriving this, because I keep on ending up with stuff like the inverse of pi rather than pi and 1/L^3 rather than 1/L^2.
This is if I decide to start with two times the integral of cos(anglefromleftofsemicircle) from 0 to pi, divided by L; since I think that gives me a coefficient.

On that topic, how do I apply Gauss's law and what is it exactly?

Test

Gen Chem class here
I tried to do a Lewis structure of PF6- and struggled to put the extra electron somewhere so I put it in as a double bond on one of the fluorides. Google said it's wrong and makes the electron float around phosphorus.

Why? I thought atoms preferred to make double bonds than just leaving electrons floating around.

Help, I started medicine school and for one of my classes I have to find an article relating to a specific subject.

My professor told us that it can't be any article of from google. And that it had to be 'An indexed medical journal"

I don't even know what to look for. I'm reading some articles but I'm not sure if it's the right thing.

What do you usually look for for these "approved" research papers?

I'm reading an introduction to quantum mechanics and I've come across some strange symbolism (this isn't the only question I will be asking during this reading), which I have been unable to find in rapidtables.com/math/symbols/Basic_Math_Symbols.htm.

Basically, it's a type of bracket: "

If I want to be a useful asset in the private sector, should I go into Physics ot Engineering?

Your school probably has access to the jstor database, if not you can search on library genesis.

I was never really interested in physics before, nor did I know what the subject was about until I started HS. There I met my professor who always taught physics in a very interesting way, trying to interest the student. That's how I became interested in physics. I started asking myself more questions, learning about particles, what materials are things made off etc.

Since primary school until the end of high school (20 now) I never really liked doing math and I always thought I was bad at it, that it wasn't in my nature, until recently, a year ago, when I decided to learn math for physics' sake.

At first, I just wanted to get through math without actually going into too much detail. You know, just learn what I absolutely must, to be able to do physics. But as I did more and more math, I actually started to like it, and I actually started understanding everything, and I realised that I wasn't actually bad at it, just that I never actually put in the time to learn it, to actually understand it.

I think I came a long way in one year, from wondering how to swap places of [math]x= \frac{y}{z}[/math] into [math]y=z \times x[/math], to doing derivatives right now.

I'm interested in physics and how shit works, particles, how they interact, why and so on, but I can't be bothered to read articles about something on for example phys org, where they go into detail about stuff. I just look at the title, pictures and skim through the article. But then again I feel that stuff is a too advanced for me and that I'm missing and still don't know a lot of physics/science to actually understand what the article is explaining.

But I feel that, to become a physicist or a scientist in general, I should be interested in all articles about science, even shit like "Scientists capture neon in an organic environment for the first time".

Do I actually like physics, or shouldn't I even bother, as I wanted to study it at uni and get a bachelors (masters and phd later)?

Anyone?

The advanced shit you read isn't interesting because it is loaded with jargon and concepts you arent familiar with.

Like if I gave you a comprehensive book on The MetaGame of DotA 2, you would have no idea how to decypher the jargon or know concepts like laning or roles. But someone who does know those things would devour that book.

You are just insecure and doubtful in your ability to learn. You want to do it and believe you can, you came a long way don't puss out now.

>Do I actually like physics
Only you can answer that question. At this point, though, you are still too inexperienced to make that judgment properly. Recall that you didn't like math that much until you actually started learning about it and understanding it. It's the same idea with anything you learn. It is easier to say whether or not you like something when you are more knowledgeable of it.

This results in some practical dilemmas. In uni, if by, say, your third year you decide that physics doesn't interest you as much as you thought it did, then you will have wasted a lot of time and money if you decide to bail out. In the case of choosing a major, the best thing you can do is go with your gut instinct.

F=ke*qQ*(r/|r|)/(|r|^2), E=F/q = ke*Q*(r/|r|)/(|r|^2)
That gives you the field E at a displacement r from a point charge Q.

For a rod with charge density ΔQ coulombs/radian, bent into a semicircle of radius R, the X component is zero (by symmetry), the Y component from an infinitesimal section is
dE/dθ = ke*dQ/dθ*sin(θ)/(R^2)

Integrating over 0 ΔQ = Q/π (3)

Substituting (2) and (3) into (1) gives
E = 2*ke*(Q/π)*/((L/π)^2)
= 2*ke*π*Q/(L^2)

>doing derivatives right now
You probably realized how physics is very tightly bound to the concept of derivatives (and integrals, the inverse concept). Velocity is the derivative of position, acceleration is the derivative of velocity, etc. In fact, this link is the whole reason calculus was invented in the first place, and there are extensions to the calculus you're currently studying that capture this relation in greater detail.

Assuming you noticed this before, did this realization give you a major nerdgasm? If so, you definitely like physics.

I'm a tad confused now.
The Y component is the derivative of a field?
And what's the d to the left of the Q?

>did this realization give you a major nerdgasm?
See, I'm the same way as that kid is about mathematics. Occasionally I do get nerdgasms; there's some pretty cool shit in math. But I still can't shake the feeling that math is somehow fundamentally boring to me.

My guess is that I'm just a young ADHD faggot who can't sit down to slog through the boring parts without a lot of effort.

The derivative stems from the fact that the rod is being split up into an infinite number of point charges.

The total field is the sum (integral) of the fields from the individual point charges.

ΔQ is the charge density (coulombs per radian) Integrating over the semicircle (i.e. multiplying by π) gives the total charge Q.

I'm aware why there's a derivative, but I don't get the thing about the Y component being the derivative.
Nor that it's a derivative of the field, yet Q is what's altered.
And that you say the total charge is Q/pi, when it's explicitly stated that the total charge is simply Q.

>>
imagine writing 1000 zeroes on a piece of paper
now imagine doing something that took 10 times that long

then 10 times longer than that

repeat 97 fucking times

it'll be longer than the universe's existance

No, it is not in fact the next logical step.
Googol and googolplex are the Sonic OCs of the number world: "LEL SO MAJOR MY NUMBER IS BIGGER THAN YOURS".
>"My number Googol is one with a hundred zeroes after it! Biggest number ever!"
>"Oh yeah? Well my number is Googolplex, with Googol zeroes after it! Bigger than yours!"
Those numbers are useless and were made with a child's logic.

There is, in fact, an actual term for one with a hundred zeroes after it; but I forget what it was.
Not centillion, that's one with 300 zeroes after it.
And millilion would be one with 3000 zeroes after it.
There's a formal, structured way of doing this without nonsense like googol.

Thank you.

Alright, all I don't get about this now is where that 1/pi comes from, I'm getting pi^2 instead of pi without it.

So I was asked to figure out a problem and I think I have the solution but since its not in my field of study I was hoping that I could find some anons I could run it by.

Problem I'm shipping black out material to America from Australia and it keeps crinkling up in transit making it unable to be used.

I believe its because the Tg of the acrylic emulsion we use as the foam backing is being breached during stages of transit.

Do user think that may be the case?

I believe the emulsion we are using is BLJ-780, Pure acrylic latex, solid: 49-50, similar to Rohm and Haas:ST954. The product is a kind of pure self-cross linking anionic acrylic emulsion and is specially designed for durable crushed foam coatings.

1 AppearanceMilky liquid
2 Viscosity, NDJ-1 viscometer, 3# rotor, 60 r/min

Suprised no one answered this. To answer the second question about the backwards 6 - that's a 'partial' derivative (as opposed to the regular d which is a 'total' derivative). The difference between them is important. Just have a google or look in a maths book. If you're still having trouble, the difference between the two is probably a good topic for a sqt.


Regarding the bracket, there are two options that spring to mind. My gut instinct says that it's talking about the average/mean/expectation value. The other is that it's Dirac notation (this is a shorthand notation used a lot in QM, but I doubt you'd find it in an introductory book until late on if at all). You'll probably have to upload a picture, or even give a book reference if it's a common book.

Anyone have a good example with answersof a stochastic program with fixed recourse if the demand isn't met?

What math should I brush up on for Physics IV? "
Examines thermodynamics, including temperature, zeroth law, thermal expansion, specific heat, first law, second law, entropy, third law, kinetic theory, Brownian motion, and the ideal gas. Also explores special relativity, including historical background, Lorentz transformations, length contraction, time dilation, invariance of the laws of physics, relativistic dynamics and kinematics, and paradoxes."

why no moon base 2016 is sooooooo fail......

>Alex Jones
You wicked, wicked DEVIL!

>my reasoning is, is googol is 1 +100 zeros then shouldn't the next step up to get googolplex be 1+ 1000 zeros has 1000 the next step from 100, so my thinking puts it together and it makes sense
Sure but when you get down to it the naming convention is arbitrary and just means what it is defined to mean.

The word googol itself was made up by like a 4 year old.

There's no context in which that sentence isn't completely wrong.

I've watched the context, it's just as dumb.

>Bills with the number 666 are always bad bills
>666 is built into the "bar code algorithm"
>Explains this by saying that 666 = 2*33 and that 33=pi

The context is that he's a fucking moron

X is a positive random variable.
why is the random variable equal to the integral over the characteristic function?
why is the expected value of the characteristic function equal to the probability?

2nd question resolved

1st question resolved as well
thanks Veeky Forums

i just started this but isnt this example wrong lmao

shouldnt it be [math]\frac{-2\pm \sqrt-4}{2}[/math]

Yes, they fucked it.

Also >has no solutions
>What are complex numbers?

oh, this is teaching us complex numbers, so that was the point it was kinda making.

but i cant believe they fucked up the example like that

I guess they prematurely divided by the denominator. At least the mistake is easy to spot!

Good luck with the complex numbers!

> I don't get the thing about the Y component being the derivative.
The Y component (of the field) isn't the derivative, it's the integral. I.e. the derivative of the field w.r.t. the angle is the portion of the field from that angle.

> dE/dθ = ke*dQ/dθ*sin(θ)/(R^2)

The charge density ΔQ is the derivative of charge w.r.t. angle: dQ/dθ

Integrating both sides makes the derivatives disappear:

> E = ke*integral[0,π] ΔQ*sin(θ)/(R^2) dθ

> And that you say the total charge is Q/pi, when it's explicitly stated that the total charge is simply Q.

The total charge is Q. The charge density (charge per unit angle = ΔQ = dQ/dθ) is Q/π (Q coulombs divided by π radians).

> ΔQ = Q/π

You're probably trying to do this intuitively, I'm taking a more formal approach. But the only part of it that's non-trivial is

> integral[0,π] sin(θ) dθ = 2

Everything else is a constant or trivially-derived. In particular, dQ/dθ is constant, and equal to Q/π (the total charge divided by a semicircle). Similarly, the radius R is just L/π (a semicircular arc of radius R has length L=π*R).

Note that calculating the X component would be similar but with sin(θ) replaced by cos(θ), giving

> integral[0,π] cos(θ) dθ = 0

i.e. the left and right halves cancel out.

Will employers look down on me with a Philosophy degree?

> all I don't get about this now is where that 1/pi comes from
Field strength is proportional to the charge and inversely proportional to the square of the distance.

Charge per radian is (Q/π), radius is length per radian which is (L/π).

That results in (Q/π) in the numerator and R^2 = (L/π)^2 = (L^2)/(π^2) in the denominator. (1/π)/(1/π^2)=π^2/π=π.

I hate math. Can I go the rest of my life without math? (Talking about calculus, advanced math etc.) Basic stats and all that I already know. How detrimental could this prove to be? Tell me the truth without STEM memes, please.

>"LEL SO MAJOR MY NUMBER IS BIGGER THAN YOURS"
And it still can't even hold a handle to TREE(3). So glad Wildburger ended this faggotry.

learning universal properties
haven't found a very good explanation so far
my textbook has only given me examples of universal properties without actually defining what they are
would it be correct to say that if a construction has a universal property (or is universal), it induces a unique morphism?

more or less
I've been told understanding of UE comes with time and experience

Is material science and engineering a good field to go into? Are there jobs? Does it pay well?

>Can I go the rest of my life without math?
Yes. Most people do. Just don't expect to live a STEM life.

And you will forever be a brainlet, too.

How would you find the Taylor polynomial for the function cos x/(1+x)^1/5 without differentiation??

How do step up transformers work? Where do they 'get' the extra voltage from if the incoming voltage is lower?

As far as I understand, they don't spin.
They react with a surrounding EM field a certain amount. This amount can be mathematically simulated by a imaginary particle spinning.
But that is like saying 3 cars weighs the same as an elephant - it works mathematically but hell no, a car isn't a kind of elephant.
Actually if you try to estimate the spin speed as if if it would be a spinning top, the particle would have to spin faster than the speed of light - so 'spin' is a bit like charge, it just is and know one really knows why.

not

alt: wolframalpha

Voltage is energy per charge. On the step-up side of the transformer the energy is packed into less charge, the total power (energy per time) is conserved. For more in-depth explanation lrn2electromagnetism.

le transformers XD Autobots!