/sqt/ - Stupid Questions Thread

surface integral

thanks

No, it doesn't even hold in R^3.

isn't the strong form defined over Euclidean space in at least three dimensions?

>defined
So the Riemann hypothesis holds over [math]\mathbb{C}[/math] then?

>Any two bounded subsets of 3-dimensional Euclidean space with non-empty interiors are equidecomposable.

Is merely stating things sufficient for them to hold?

Explain to me what a cover is

I mean, just read the papers on it. Seems like you either don't know what's up or your anti- axiom of choice and purposely omitting it from this discussion in hopes of more (you)'s.

>just read the papers on it.
Any proof of "Banach-Tarski" reduces to showing that the result holds assuming [math]0 = 1[/math].

Cool.

They don't "push off" anything.

Stupid question:
Why do beings that get their sustenance by photosynthesis mostly stay in one place?
I mean, why can't you have some kind of insect that drinks water from the oasis and then flies off into the desert to photosynthesize for a bit?

Not doing the math, but I assume you can't make ends meet using only photosynthesis.
Photosynthesis has terrible efficiency, so you need a lot of illuminated surface area even without active movement. This in turn means that you would have to carry a lot of mass around, which would take even more energy.
In contrast, it is efficient to eat photosynthesizing plants, since they have already done the gathering and processing.

Fuck off gorilla nigger, this is a place for smart gorillas only. I watch you brainlet with disdain

I secondo this

Can you do an integral under a straight line?

of course

how does the formula look like?

well it depends on the line, doesn't it

if the line is y=mx+b
and I want the integral from f to g (on the x axis), and f < g

[math]\left. \left( \frac{m}{2}x^{2} + bx \right) \right|^{g}_{f}[/math]

why isn't there a ∫
?

Does any one of you guys have that pic with recommended books from basic maths to advanced stuff?
I usually see it a lot around Veeky Forums, but now that I want it I can't find it.
Thanks in advance!

The rules of integration is the same for any curve. Try it out:
>Integrate a line like y = 2x in an interval like 0 to 4
Then compare the results with
>The area calculated with the triangle area formula

Then, I'd suggest you how to get to the integration rules by using its definition, that is, try to understand how the idea of the integral's been developed. Don't just memorize things.
Good luck!

It's a fucking meme, just go to the Veeky Forums wiki, it's linked in the sticky. If you want more help, go to /mg/ and ask concrete questions, but the wiki books are pretty good, so I recommend you pick a textbook and stick to it rather and trying to find THE textbook, because you won't.

did anyone here have math anxiety at some point?
the idea of entering my calc class and flopping over the material gives me such a tiresome headache.
i want to master it though.

Thanks!
Actually, it's for a friend of mine. He's trying to learn basic maths and I don't really know what to suggest him and I can't suggest him the books that I'm used to because he won't understand a thing.
I'll take a look at the wiki then!

You mean, like bored?

I've already integrated. [math]\int_{f}^{g} (mx+b)dx[/math] is precisely what I have there

That's the evaluated integral

how do i get over boredom

By doing something you enjoy. If you don't like math (or at least that field of math), then don't bother forcing it. Try exploring different fields inside and outside mathematics, maybe you'll find something that you enjoy.

Or you could attempt different problems inside that field. For example, in calculus, you could try some applications in physics or optimization, and if you're more into pure maths, you could try analysis.

So how is thrust created?

what does the d in dx stand for?

Derivative notation.

dick

Have you even tried reading a calculus book?

Doesn't the -1\12 meme just prove that math is stupid?

>Doesn't the -1\12 meme just prove that math is stupid?
What do you mean?

what do you guys think of this article?
colddarkstars.wordpress.com/2017/09/01/the-univariate-mind-of-the-far-right-crank/

It's common notation now, but historically its an artifact from when calculus used to be done with infinitesimals.

It proves that anyone who believes regular summation can give you that answer is stupid, actually.

[math] \lim_{x \to x_0}f(x) = L [/math] if for every [math] k > \delta > 0 [/math] where [math] k [/math] is any real constant, there exists [math] \epsilon > 0 [/math] such that [math] 0

sorry for repeating myself...

In my mechanics course a potential force is defined as such that there is a scalar function [math] \Pi (t, \vec r) [/math]
[math]
F(t,\vec r) = - \frac{d\Pi}{d \vec r}
[/math]
The problem is my calculus course hasn't yet covered much of vector calculus. How am I supposed to differentiate by a vector?
And why is this true, if the force doesn't change with time i.e. [math] F = F(\vec r) \ \ \Pi = \Pi(\vec r) [/math]?
[math]
\delta A = \vec F \cdot d \vec r = - \frac{d\Pi}{d \vec r} \cdot d\vec r = -d \Pi
[/math]

>mfw have higher IQ than the average basketball american

Oh wait, it says.
[math]
\vec F (t, \vec r) = - \frac{d \Pi}{d \vec r}
[/math]
So, the derivative of a scalar function is a vector somehow. I'm confused even more now.

What are both the cons and pros of choosing Chemistry over Chemical Engineering?

>How am I supposed to differentiate by a vector?
en.wikipedia.org/wiki/Directional_derivative
But in your case you're supposed to use gradient
en.wikipedia.org/wiki/Scalar_potential

So basically what my lecturer meant by [math] \frac{d \Pi}{d \vec r} [/math] was [math] \nabla \Pi [/math] ?

The scalar field has values for points in space. The force is proportional to the rate of change of the potential, but the potential can change at different rates depending on which direction you want to go from the same point, hence the vector quantity.

I'm no mathematician but it's pretty intuitive if you think of scalar fields as things like temperature or electric potential.

Yes. Gradients are easy to visualize in 2d scalar fields - you see them all the time, in terrain maps. Altitude is a scalar value, but the gradient (directly uphill/downhill) has a direction.

By ejecting material at high speeds

Is the electric field the source of the difference in electric potential? Or is the difference in electric potential the source of the electric field?

The former.
Without an electric field there is no potential. It's by definition one of the characteristics of an object inside a force field.
The difference in electric potential creates current.

Thanks senpai.
>+ rep

can there be a non prime number that isn't divisible by single digit numbers?

11*13

V=5
E=0
Potential, but no E-field

> An electric potential is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration.
> inside a field
If "field" also means something else, correct me. Physics lessons in high school are starting to fade away, it's very likely I made a mistake, by applying analytical mechanics terminology to electrostatics.

Does reading improve intelligence? Also any recommendation to not be stupid?

Veeky Forums is full of mental defects, so i bring this here

for those here that dont know, whey is a quickly-metabolized protein; maltodextrin is a trisacharide that is absorbed practically like a monosacharide; and mct oil is a medium-chain triglyceride, also very quickly absorbed

after a workout, would it be better to consume a shake of whey and maltodextrin to spike your insulin but in doing so lowering test for a few hours(insulin being antagonistic to test and hgh); or would it be better to consume whey and mct oil for similarly quick absorption, but im not sure how it affects insulin/test/hgh?

Can anyone else not make new threads? Getting error.

is Veeky Forums broken?

i keep getting posting/uploading errors too

test

no

I cant post

cant post images
reee

Not a single (You) after 8 hours :(

pls respond

What's to explain? An (open) cover of a set is literally a bunch of sets that cover the set (i.e. their union contains the set).
For example (-1,1), (0,2) cover [0,1].

@9454998
(YOU)

STILL CAN'T UPLOAD IMAGES REEEEEEEEEEEEEEEE

Wikipedia is giving me conflicting information. Which of these is correct?
>The absorbance of an object quantifies how much of the incident light is absorbed by it (instead of being reflected or refracted).
>The term absorption refers to the physical process of absorbing light, while absorbance does not always measure absorption: it measures attenuation (of transmitted radiant power). Attenuation can be caused by absorption, but also reflection, scattering, and other physical processes.

I'm guessing the latter. Also what is "apparent" absorbance? Is this a technical term, or do they mean the laymen definition of apparent (so I suppose meaning "as measured")?

so they literally push off the matter they eject, brainlet

What does it mean that the universe is holographic? What kind of mickey mouse engineering is god doing?

>Is this a viable alternative to the conventional epsilon-delta definition of a limit?
What have you tried?

Different groups might use different terms. The exact definition of the term is not critical, just figure out what absorbance is referring to in the context it's used. I think the former is what is usual meant though, it would be odd to use absorption in place of attenuation.

When will I know if the MemeDrive works? Will I be able to tell by the dramatic rise in suicides among STEM degree holders?

Except the engineers. I, for one, welcome our new Veeky Forums overlords.

Hello, could you please give me some nontrivial examples of two subgroups, which have only identity elements as intersection?

Thanks!

Ah, you're right. I didn't notice but the latter is used for chemistry, where the former is physics. Chemists are indeed an odd bunch.

if I have two vectors, how do I find out the area enclosed by them as a triangle?

I'm doing a review of chemistry from a maths background:

WHY is bond order inversely proportional to the bond length? Everywhere on google just gives results where they mention this fact but don't mention why it makes sense

The parallelogram is given by the determinant of the matrix with columns as those two vectors (in clockwise order). So the triangle is simply HALF the parallelogram and so is half the determinant.

does that mean I use the cross product, take it's magnitude and half it?

How trivial is trivial?
The symmetric group on 3 elements S3 (isomorphic to D3 the dihedral group on the triangle):

[math]S_3 = \{1, (1 \ 2), (1 \ 3), (2 \ 3), (1 \ 2 \ 3), (1 \ 3 \ 2) \} [/math]

Then the subgroups here can be the rotations and the reflection group

[math] A = \{1, (1 \ 2 \ 3), (1 \ 3 \ 2) \} [/math]

[math]B = \{1, (1 \ 2) \} [/math]

yes sir