/sqt/ - Stupid Questions Thread

1 is not a prime number, so no.

How do you obtain 6,42 with three numbers you can multiply or add between themselves?
I know 1+2+3=6 and 1*2*3=6 but 6,42?

I have been seeing some symbols recently.

What does the upside down A mean? It's like a V that has been stroke through by an horizontal line.

Also, what does a '.' mean? It's basically three points forming an upside down triforce. I know the upside down of this upside down means "therefore"?

Multiply top and bottom by [math]a[/math].

What does this even mean?
[math]6,42 + 0 + 0 = 6,42[/math]

But 6,42 * 0 * 0 = 0 and not 6,42

Can someone walk me through this I feel like a fucking retard. The farthest I got was tan^2(x)+tan(x)=1 but I still can't figure out how to get x.

Sleep deprivation definitely has a hand in this but I wont be able to sleep until I figure this out.

Oh. If that's what you meant, then just set [math]a + b + c = d[/math] and [math]abc = d[/math] and use Vieta because they are symmetric sums.

You can solve it like a quadratic. Because it *is* a quadratic.

sec + 2 = 2sec + tan
2 = sec + tan
2 = tan^2 x + tan x + 1
tan^2 x + tan x - 1 = 0

That is a quadratic that you can solve for tan x and then get the inverse tan of that to get x

The upside-down A means "for all." It's should be accompanied by some variable, like x. So you would see [math]\forall{x}\in{S}[/math] ... followed by some proposition. It would be read "for all x in [some set] S, such-and-such is true."

You may also see a backwards E, which is similar and means "there exists (at least one)..."

The second symbol just means "therefore."

Any good intro book on logic or proofs should go over this stuff. It's useful to know.

Sorry, the second symbol means "because..." not "therefore." Didn't read

>quadratic
holy shit I really am retarded. Didn't even consider that, thanks niggas.

I'm too retarded to understand how to use it. Care to explain?

Medical question for a medical novel idea, could a single surgeon with the best training and equipment perform a organ transplant single handedly and if not what's the bare minimum of people needed?

So I'm trying to derive the Kline-Gordon equation from the action, taking [math] \mathcal { L } = - \frac { 1 } { 2 } \left (\partial ^{\mu} \varphi \partial _{\mu} \varphi + m^2 \varphi ^2 + 2 \Omega \right )[/math]. Then [eqn] \delta \mathcal { S } = - \frac { 1 } { 2 } \int \operatorname { d } ^4 x \left ( \partial ^{ \mu } \delta \varphi \partial _{ \mu } \varphi + \partial ^{ \mu } \varphi \partial _{ \mu } \delta \varphi + 2 m^2 \varphi \delta \varphi \right )= 0[/eqn] Now I'm not quite sure where to go from here, I've read that you perform integration by parts on the first two terms (and require that the [math] \delta \varphi [/math] vanish at infinity to remove the boundary terms), but I don't know how to do parts on an integrand like this. Anyone have any tips and general pointers?

Is it possible in our lifetime that we will see reverse aging?

Wouldn't it require to multiply every place to a instead of a single factor?

No. If you multiply one factor by a/a, then you're multiplying by a form of 1, which is valid.

Thanks.

You want to use IBP to reduce the terms proportional to the derivative of delta phi to being proportional to only delta phi.

Then the integrand is proportional to delta phi, which gives you the differential equation.

How much Calculus do I have to know before I can start working my way through a physics textbook?

Depends. But really you know up to vector calculus, but you'll be able to read some introductory books with just single variable calculus.

Multplying top and bottom by a would give 4ac/a^2 and not 4ac.

How practical is chemistry as a career really? Ive always been told that it was a wonderful career choice and its always been my dream to go to graduate school and get my PhD but im starting to have second thoughts. Ive been doing research work for two years and have a few minor publications with a major one coming within the year and yet the professor I work with makes about $65k a year and he doesnt seem all that happy with how things have turned out for him. The mans a complete genius, got his PhD in 2 years in Germany before moving to the US to teach and it seems as if ill never be on his level of pure knowledge when it comes to the field. If even he didnt make it big when he seemed to be a golden boy in school im starting to believe that I shouldnt go through all that schooling only to end up in a position doing grunt work or teaching entry level classes for 1/3 less pay than someone with far less education and training.

I know its anecdotal evidence but im starting to think if I should just give up and go into medical school or just be a retail pharmacist like my dad.

Why don't you just do what you enjoy?

People can enjoy several different things, so unless you are some sort of autistic monomaniacal retard, it is logical to consider which of your interests will be a more feasible career.

No.

Yeah it looks like a mistake...

[eqn]-\frac{b}{2a}\pm\sqrt{\left(\frac{b}{2a}\right)^2-4\frac{c}{a}}=-\frac{b}{2a}\pm\sqrt{\frac{b^2}{4a^2}-\frac{4c}{a}}=-\frac{b}{2a}\pm\sqrt{\frac{b^2-16ac}{4a^2}}[/eqn]

I'm guessing it should be

[eqn]-\frac{b}{2a}\pm\sqrt{\left(\frac{b}{2a}\right)^2-\frac{c}{a}}=-\frac{b}{2a}\pm\sqrt{\frac{b^2}{4a^2}-\frac{c}{a}}=-\frac{b}{2a}\pm\sqrt{\frac{b^2-4ac}{4a^2}}[/eqn]

because I believe in being pragmatic and being surrounded by professors far smarter than I will ever be who dont seem to be all that thrilled with where they are today its making me lose faith that this is the right choice for me. Im far from being in it for the money but im still seeing a top 20 globally ranked school graduate with 15 years of experience work 60 hours a week teaching dumbshit undergrads all while trying to produce publications and having to jump through all the hoops that being a professor at a public university entails only to end up under appreciated and underpaid.

I love chemistry I really do but im starting to think more and more about just taking the easy route.

>im starting to think if I should just give up and go into medical school or just be a retail pharmacist like my dad.
These don't sound like the words of a person who would seriously enjoy the other options available.

I enjoy painting but I sure as shit wouldnt consider making it a career

Why not do research in industry? There's probably some cool shit out there.

That has always been my goal which is why I posted in this thread in the first place to see if anyone actually had any experience in the field. Im surrounded by academics both at work and in class so I havnt got to speak with many people on the industrial side of things.

Tourist here.

What are effective theories exactly?
Universe Review (from sticky) describes them as theories with unmeasured parameters, while Wikipedia describes them as '[...] theor[ies which] proposes to model a certain effect, without proposing to adequately model any of the causes which contribute to the effect.'

Can Veeky Forums clarify?

From what I remember, effective theories are those that have been proposed based off already existing theories but are still being tested. Take, for example, theories based off the Standard model such as string theory.

Yeah, that would be right. It's supposed to be (p/2)^2-q, with p = b/a and q = c/a.

Not exactly helpful desu.

Going through Rudin. In his discussion of the Cantor Set, he states
>No segment of the form [math]\left(\frac{3k +1}{3^m}, \frac{3k +2}{3^m}\right)[/math], where k and m are positive integers, has a point in common with the Cantor set.
Can someone explain why this is the case?

Why do scientists use Latin (in vito, ab inito) in publications? Who started this pretentious trend?

The same people that started science itself. You will also find a lot of greek and some arabic terms.

That term has a specific technical meaning in quantum field theory. Is that what you're asking about?

what are the best books for proves, topology and calculus? (and why)

you sound like you don't know what you're doing at all. why do you want to learn topology with calculus? that's called analysis. if you want analysis, go for Terence Tao's Analysis I.

Is there any (micro)biology branch that requires heavy math knowledge?

Do light years have a leap year every 4th light year?

kek

(It is based on the Julian year, for everybody actually wondering)

I found this in a textbook that was recommended to me. I don't understand, shouldn't 0/0 be undefined? Why does the book allow me to do it?

No. Biology is for brainlets.

(I didn't know Tao wrote textbooks...)

Systems biology

0 | a is the same as saying a = 0x for some x. So a must be 0. It's just saying that if 0 is only ever a factor of 0.

It's just saying that 0 is only ever a factor of 0. *

But playing God with some micro-faggots sounds fun as fuck.

one book for proves
another book for topology
and a third book for calculus

I overlooked that. Does that mean that the operation itself is possible, but that 0/0 doesn't have a defined outcome?

Here with another retarded geometry question.

DE // AB, AF and BF are bisectors of the angle A and B respectively, AC = 8 and BC = 12.
How do I find the perimeter of triangle DEC?
I'm starting to get a little frustrated. I've tried with a lot of theorems, including Thales and a lot of weird proportions. I think it can be solved with a system of equations, but still can't figure out which one.
A hint or the solution would be greatly appreciated.

In a way, yes. Because, in the example a = 0x, the factor x can be anything, x = a/0 = 0/0 is considered undefined. Otherwise, we could replace 0/0 with whatever number we want whenever we encounter it, and we would pretty much break mathematics.

Just remember that the statement "0 | a" is just a statement that is true or false - "0 is one of the factors of a" - unlike the statement "0 / a" which is an actual numerical value.

How can I understand maxwell's equations beyond just knowing the formulae

An intuitive sense, how

The only thing I know is there are no magnetic monololes, which i only know because i remember that phrase. I don't know why specifically that it is so..

>magnetic monololes

>monololes

You might wanna keep reading.

No, I don't think so. I stumbled upon this term in Introduction of universe-review.ca/F01-introduction.htm#evolution, so I don't think author had quantum field theory.

*in mind.

Phone posting in suffering

There's a book called Electrodynamics by Fulvio Melia that starts with the derivation of maxwells equations from physical observables. I think it's pretty well done.

I study neuroscience. Applying to a masters program next year in cog/neuro.
Should I learn html/css/javascript etc? or just go into C and such?
I have the fundamentals down, as I studied CS for a year.

ive read that psychologists use python and some proprietary languages to develop tests and automate results, I just want to know what you guys think.

just a reminder, this is a stupid questions thread

If my universe is all Real numbers, and I'm referring to ALL Integers (not all Reals), would I say:

(∀x)(x is an integer)
OR
(∃x)(x is an integer)

I was watching Meme Academy, and I witnessed Sal derive a kinematic formula, [math]\vec{s}=\vec{v_o} \Delta t+\frac{1}{2}\vec{a}\Delta t^2[/math] . I mean, it's all cool and shit, pretty simple, easy, but how the fuck could I ever derive this on my own, without even knowing what to use as a substitution instead of something in the equation?

Is this one of those formulas, that you just learn to derive by heart, just because x is something that must absolutely be substituted by (y+z), even though it could be also substituted by 2(p+q), but if we did that, it wouldn't work?

Like, how the fuck do I learn what to substitute for what to derive my formulas? There must be a logical solution to this, right?

[eqn]\forall{x}\in\mathbb{Z}[/eqn]

REKT

Thanks. So I'm allowed to use ∀ to refer to any other universe or just a sub-set of the universe I'm using?

Things like this crop up all the time. Oftentimes the derivation of a formula involves a trick or two that you would never have thought of. That's because it's all built on knowledge that's been developed for centuries or decades by a few clever people.

So the best thing you can really do is make the most sense of it that you can. Remember the general gist of it, as well as whatever specific trick there is.

Anyway, you shouldn't expect to remember how to derives the kinetic formulas. Just get the gist of their derivations, then remember them and use them. It's like how you remember how to add and subtract, but you don't count on your fingers each time. It's just natural, and there are bigger things you should be worrying about.

Yes, you can use it for any set; doesn't have to be limited to the universe. What I wrote is read "for all integers x..." and limits the discussion to the integers. It's all very flexible.

why exactly can i do that? what exactly am i doing here? is there a related proof?

"gesamtheit" = all
"vollständig" = complete (? ì guess)
"zulässig" = allowed
"entwicklung" = expansion

This seems like a pretty big step and all of it got left out..

I need to find the limit of x as x approaches infinity

The equation is -(3x^2)/(4x+4)

Is the answer to this -1?

The entirety of the "eigenfunction" (seems like everybody uses the german term?) of a hermetian operator is complete in the following sense:
Every (allowed) function x can be represented as a development according to the orthonormal eigenfunctions

Nope.

[eqn]\lim_{x\to\infty}\frac{-3x^2}{4x+4}=\frac{-\infty}{\infty}[/eqn]

Use L'Hopital's rule:
[eqn]\lim_{x\to\infty}\frac{-6x}{4}=-\infty[/eqn]

Is not (-infinity/infinity) = -1?

Also, I'm beginning my Calc 1 course and this is from a pre-calc review homework sheet. I haven't learned L'Hopital's rule

no, read indeterminate forms, L'Hospital's rule, etc.
Infinity isn't a number and doesn't follow algebraic relations defined on the real numbers. ESPECIALLY at the level of intro calc, remember something like 'infinity' is sloppy for 'the limit of this expression as x approaches [value] is unbounded from above.' An infinite limit can be useful in terms of notation to denote whether it diverges off to a positive value or negative value, or if it just oscillates wildy or becomes a discrete jump such that the limit doesn't exist.

Just an addition to , you take the eigenfunctions to span your function space. If you're not familiar with complete sequences of a function space--which is really the business of functional analysis where you start to get picky about the technicalities--think of it like a Fourier series expansion of a function. The sines/cosines make up the basis (function) vectors and the coefficients define the function. Same thing for an eigenvector (function) decomposition of a general function in QM.

That's a good thought, but you can't "divide out" infinity like that. Basically because infinity in this context isn't actually a number per se, but representing an *approach* toward infinity.

[math]\frac{-\infty}{\infty}[/math] is one of many "indeterminate forms" and you'll learn more about this and L'Hopital's rule in Calc 1.

For now, I'm guessing they just want you to say that the limit is undefined. How is the problem stated?

Damn, that's depressing.

I realized I couldn't divide infinity like that, so I looked up indeterminate forms and I understand it a bit. This is how I approached the problem. Can you tell me if this is correct?

I circumvented the problem by dividing each term out by x, which reduced the problem to -(3x)/(4+4/x) which I reduced to -infinity/4

Which the answer to that is -infinity. Did I do this right?

>think of it like a Fourier series expansion of a function
this is pretty much how i thought of it - i just don't see the point that you can present for ANY problem a solution in the form of fourier or orthonormal eigenfunctions or w/e is still out there without me knowing about it

Yes that's correct.

Remember that technique, by the way. It comes up a few times.

Is there a way to have a bond (or double or whatever) to go through benzene ring?
If not whats the smallest size ring that can have bondings go right through the middle? no fucking clue how to google that

pic related

The closest I could think of is hapticity, pic related.

Well normally you can get somewhere by going to first principles, so in this case you could say "assume that acceleration is constant", then you get the differential equation [eqn] \frac { \operatorname { d } v } { \operatorname { d } t } = a [/eqn] When we integrate it, we get [math] v = at + C [/math] Now we need to determine C, we can do this by noting that when [math] t=0 \implies v_0 = C [/math]. But velocity is just the time derivative of position, so [eqn] \frac { d s } { d t } = at + v_0 [/eqn] Again when integrating we get [math] s = v_0 t + \frac { 1 } { 2 } at^2 + C [/math] like before we look at when [math] t=0 [/math] notice that this implies [math] s_0 = C [/math] but what's the displacement when t=0? We normally take it as [math] s_0 = 0 [/math]. Which gives us: [eqn] s = v_0 t + \frac { 1 } { 2 } a t^2 [/eqn] The only advice I can give is go back to basics whenever you need to.

Thanks for the help. Another question:

Find the limit of x as x approaches infinity. Equation is ((-e^-3x) - 1)

cooked that ferrocen in a lab once - god was this a bitch too clean from the sublimation apparatus - this also the closest one i knew about but this question came up in a discussion and i had actually no clue how to adress it

That one's pretty simple. Hint: don't get tripped up by the e.

The limit as x approaches infinity of a^x is infinity for any a, given x is positive...

Just installed TensorFlow through Windows Bash and was wondering what resources I should be reading to understand what's going on in example demos.

How would I be able to access the TensorFlow folder with Windows Explorer?