/sqt/ - Stupid Questions Thread

>the virgin horse-cock
>the chad pearly penile papules

en.wikipedia.org/wiki/Descartes'_rule_of_signs

As the intellectual Donald Trump would say, WRONG

y=-x^3-5x^2-5x-1

How does gravity explain helium balloons? We all know helium rises because it's lighter than air, but how can it be lighter than gravity? What force is pushing the balloon "up"?

Okay, so consider the operator [math]\frac{d^2}{dx^2} + 1[/math]. I'm supposed to find its Green function satisfying the conditions 0 at 0 and derivative wrt [math]x[/math] 0 at 1. My attempt was to set [math]G(x, y) = \alpha_1\sin x + \beta_1\cos x[/math], when [math]x y[/math]. I can, probably, assume 0 and 1 are the boundaries, since those are what are given, so [math]y \neq x \Rightarrow G(0, y) = \beta_1 = 0[/math], and [math]x \neq y \Rightarrow \frac{\partial }{\partial x}G(1, y) = \alpha_2\cos 1 - \beta_2\sin 1 = 0 \Leftrightarrow \alpha_2 = \beta_2 \tan 1[/math]. If I demand this function is continuous when [math]x=y[/math], then [math]\alpha_1 \sin y = \beta_2\tan 1 \sin y + \beta_2 \cos y \Leftrightarrow \alpha_1 = \beta_2 (\tan 1 + \frac{1}{\tan y})[/math]. Can I take this further, or is this the bitter end?

Gravity is pushing nitrogen and oxygen molecules down harder than it pushes down helium molecules.

The nitrogen and oxygen displace the helium, pushing it up.

TL;DR Balloons actually float due to gravity.

Why does gravity push down less on helium?

Because helium atoms have less protons and neutrons, and hence less mass.

In general, the higher something is on the periodic table, the less dense it will be.

Wrong! If you picture a Helium balloon, that ballon is surrounded by heavier air. Including air on top of it. If the air on top of it is being pulled down, how come this does not push down the balloon?

Buoyant forces. The same force that makes bubbles rise up when underwater.

gravity pressure gradient.

that's all.

the higher you go the lower the atmospheric pressure is.

this means that if you follow the boundary of the balloon from bottom to top, the air surrounding the balloon will have lower and lower pressure on the balloon, resulting in a net upwards force.

The object only floats when this upwards force beats the weight of the object.

And that only happens when the object's density is lower than the air's.

If you want to know more, google buoyant force and stop annoying others. The math is there and it's simple.

Okay Mr. Smart, then what would happen if the balloon was filled with normal air, but the surface of the balloon was made of Helium. Where would it go?

Therefore atmospheric pressure = gravity? What differences do they have exactly?

how do I find this limit? it should be -oo

into the sun, where it would sink because air is denser than the sun's helium.

not really.

atmospheric pressure is a function of altitude, and that's because we are in a gravitational field that's oriented vertically.

it goes to -infinity indeed.

(x+1) goes to 1

ln(x) goes to -infinity

sin(x) goes to 0+

1*(-infinity)/(0+) = - infinity

*barfs

isn't that an undeterminate form?

Try l'Hôpital

l'hopital doesn't always work if it's not an undeterminate form.

this one trivially diverges to -infinity

How much is 1+1?????

That's just a long-winded way of saying atmospheric pressure is gravity.

Polemicist

Experimental psychology/statistics question.

I've got a quasi independent variable (dichotomous/yes or no question) that I'm examining the correlation with an interval (continuous) dependent variable.

I am running a second correlation that uses the same quasi independent variable from the first correlation, but this time it's the dependent variable. Can you flip a quasi IV like that to a regular dependent variable in a separate correlational/nonexperimentall test?

If something moved at speed 3c from point A to point B and back to A, would there be any way to verify that the something did that and was not stationary?

>If something moved at speed 3c from point A to point B and back to A, would there be any way to verify that the something did that and was not stationary?
Don't take my answer for a good one. I am just another hobbyman.
Provided that could happen (it can not), I guess the object would disappear forever, since B, A, or any point its movements, would be located in undefined time in the future ("infinite").

If you try to put those numbers in a lorentz transformation, you will see that you end up with weird things like "imaginary time".

>infinity
No such thing.

true

it's just a thought experiment of course. I'm not limited in my ability to entertain thoughts based on inexistant objects.

Just assume [math]0 = 1[/math] next time and get the theorem you want. It's a lot easier.

When are tidal gauges going to show significant acceleration in water level rise? Lets say 10% faster over 30 years than the early part of the 20th century (which was before oil use grew explosively).

Give me a prediction, maybe I'll remember it at old age and get a laugh "fucking morons like that was what we destroyed our economy for".

I can do that, but the guy asking can't.

>I can do that, but the guy asking can't.
I'm not a "guy".

Why not? He's already assuming something provably equivalent.

You're not the guy he is talking about either, faggot.

Global warming myth BTFO!

couldn't care less, guy.

I'm not your "guy", buddy.

this is /sqt/, you should try /mg/

I'm not your buddy, pal.

Just report the retard, he has been shitting up every single thread on this board.

>retard
Why the ableism?

Well I'm not your "pal", friend.

Atmospheric pressure is created by the effect gravity has on gasses.

wait I have the farts because of gravity? neet

Trying to figure out some good places to mutate in this protein in order to see if it'll take in different amino acid substrates. I'm looking at this protein sequence alignment for guidance, but I'm having trouble understanding it. Anyone have any tips for doing shit like this?

Someone post the picture with the math books pls

What board is smarter, Veeky Forums or Veeky Forums?

>What board is smarter, Veeky Forums or Veeky Forums?
/pol/

>
>>What board is smarter, Veeky Forums or Veeky Forums?
>/pol/
/b/

Do you know the boundary conditions at infinity?
If you do then do a Fourier transform.
warosu.org/sci/thread/S9263958#p9264355

Neither

Are animals likely to experience heat from chilli and cold from menthol?

The bigger the penis the better for pumping out other mens sperm. They think that why humans have proportionately much bigger penises than other animals, it's because the women were sluts and the biggest dick removed the most semen.

Is it gonna rain today

ncbi.nlm.nih.gov/pmc/articles/PMC4888289/

It's also why the human penis is shaped like a plunger and other animals are not.

>Capsaicin is also used to deter pests, specifically mammalian pests. Targets of capsaicin repellants include voles, deer, rabbits, squirrels, bears, insects, and attacking dogs.[48] Ground or crushed dried chili pods may be used in birdseed to deter rodents,[49] taking advantage of the insensitivity of birds to capsaicin. The Elephant Pepper Development Trust claims the use of chili peppers to improve crop security for rural African communities[citation needed]. Notably, an article published in the Journal of Environmental Science and Health in 2006 states that "Although hot chili pepper extract is commonly used as a component of household and garden insect-repellent formulas, it is not clear that the capsaicinoid elements of the extract are responsible for its repellency."[50]

It appears that capsaicin exposure doesn't effect birds, but most other mammals can feel it.

Is there a scientific explanation as to why meme-"depression" feels so good?

en.wikipedia.org/wiki/Catharsis

I don't know which board to post this on. It's related to video games but /v/ is such a garbage ass board that I won't even bother

Could there be a connection between one's capacity for empathy and being good at multiplayer video games?

I'm quite empathetic as a person. I'm very good at reading people's emotions and moods just from their non-verbal behavior, and upon reading stuff like news stories I involuntarily end up feeling like shit when I read about bad stuff happening to people.

Now coincidentally, I'm very good at multiplayer games, but specifically only the multiplayer aspect. It feels like I can very often predict what people are going to do, and that allows me to outmaneuver them. I can also tell when people are upset or frustrated, which I can usually use to my advantage in some way. I usually beat people by getting into their heads and overwhelming them by predicting their moves. However, I'm horrible against intelligent AI opponents if they're not completely predictable, and also pretty bad against players who have a non-sensical playstyle. I try to predict their actions, but there's nothing to predict since they do things randomly. When it comes down to it, I'm mechanically not that great of a player, I just have good intuition and predictive abilities.

No, there isn't.

Could someone please explain to me valancy and valance elections and the difference between them please.

I only know u(0)=0=u'(1), where u is the function I could solve if I had the Green's function and knew what function the operator turns u into.

Can any mathematicians help a physics brainlet out?

I'm trying to derive the stability conditions for the Lorenz attractor generally. The way to go about this for a typical flows problem is to find the Jacobian and solve for its eigenvalues. If the real part of all of the eigenvalues is negative, then all flows at points close to the stationary point go into the point, so it is stable.

The Lorenz attractor is a 3D problem, so we get a cubic polynomial to solve for the eigenvalues. The problem is characterised by three real parameters, which give rise to three degrees of freedom in the polynomial, so the set of possible polynomials is all of the cubic polynomials with real coefficients, which we can write as

[math]x^3 + Ax^2 + Bx + C = 0[/math]

where A, B and C are real.

The problem essentially boils down to this: What are the conditions on A, B and C such that the real part of all the roots of the polynomial is less than 0?

I made a bit of a start but didn't get too far. I set the roots to be -a, -b and -c, where a is real and b and c may be complex (in the case in which they are, c = b*). We thus write the polynomial as

[math](x+a)(x+b)(x+c) = 0[/math]

thus

[math]A = a + b + c, B = ab + bc + ac, C = abc[/math]

And we want to ensure that a, b and c have a positive real part.

I can't get much further than this. Obviously C must be positive, or else an odd number a, b or c would be negative, but once I have that condition I can't find another one that restricts the sign of the other two roots.

without loss of generality you can assume
[math] a,x,y \in \mathbb{R},~b = x+iy,~c=x-iy [/math]
Since it's a polynomial with real coefficients.
This gives you
[math] A = a+2x >0 [/math]
[math] B= x^2+2ax+y^2 >0 [/math]
and
[math] C = a(x^2+y^2) > 0 [/math]
Note that those conditions are not sufficient, but if they are not met, you won't have positive real parts

let me correct myself
>without loss of generality
is not exactly true.
You could also have 3 purely real roots, which also gives you the same necessary but not sufficient conditions for A and B

Anyone?

Valence electrons are electrons in the outermost shell of the atom.

They're the ones that actually do shit like forming bonds with other atoms, so the number of valence electrons determines the chemical properties of an atom or molecule.

If [math]lim_{x\rightarrow\infty}f(x)=\infty[/math], does this imply [math] lim_{x\rightarrow\infty}f'(x)\neq0[/math]?

No. Consider f(x) = log(x)

consider f(x) = log(x)

...

...

>he/she posted the memelist again

Please add a disclaimer: DO NOY TRY TO READ MORE THAN THE FIRST PART OF JECH

>DO NOY TRY TO READ MORE THAN THE FIRST PART OF JECH
Why not?

Which degree is harder- applied math, pure math, or statistics?

t. brainlet

They're probably equally hard.
I don't know about statistics, but if you're gonna spend years studying, I am pretty sure you will encounter some really hard shit.

They're all different man!

I think your best option, for a BS, is to do Applied Math and make sure you get your Analysis/Advanced Calculus sequence in. That's not a hard class but it's the meat and potatoes of the math world and lets you do a lot of stuff in statistics.

I did Applied Math for undergrad, Pure Math for my MS (because that's all my school has) and now i'm applying to Stats PhDs.

Studying Pure Math isn't super hard but it's really abstract. Studying stats is hardest I think, cause they make you take a lot of tests.

is ln(x) = e^ln(x) correct?

>is ln(x) = e^ln(x) correct?
No.

[math]f'(f(t)) = ct[/math]
What does this expression say about [math]f(t)[/math] and [math]f'(t)[/math]?

f can't be polynomial (except trivially 0)

if f is analytic, then f = \pm \sqrt(c)t

uhh nvm f can't be analytic

what if this was say any programming language and I just define a function called log ( x ) as a function that takes the constant "e" and does e^x where x is just a new call to the function

would this replicate the behaviour of the logarithmic function?

what the fuck are you even saying

>f can't be polynomial (except trivially 0)
can't be a Laurent polynomial either

how is ln(x) formally defined?

>how is ln(x) formally defined?
en.wikipedia.org/wiki/Logarithm#Definition