/sci/ - Science & Math

[Anonymous No.7576705]

>mfw EE professor calls Dirac's delta a "function"

[Anonymous No.7576706]

>>7576705
That's what everyone calls it, and everyone knows it's not technically a function. Stop being a faggot.

[Anonymous No.7576707]

It is a function.

<div class="math">\delta(f) = f(0)</div>

[Anonymous No.7576710]

>>7576706
I asked him if it's a distribution and he said no, it's a function. I then tried generalized function and he told me to shut up.

[Anonymous No.7576721]

>mfw biosensors prof mentions binaural beats and acting like its totally legit

[Anonymous No.7576750]

>>7576710
Oh... well he's a dick then. Still idk if it's worth arguing over. In most contexts it doesn't matter that much.

[Anonymous No.7576762]

>>7576707
This. Undergrads autistically 'correcting' their professors and still beinf wrong are the worst.

[Anonymous No.7576765]

>>7576750
No he's not. If anyone's a dick, it's jacob barnett over there stalling the lecture with irrelevant minutiae.

[Anonymous No.7576776]

>mfw biology prof implies the safety of genetically engineered crops is unclear
>mfw she uses the term "Big Pharma" unironically during lecture

[Anonymous No.7576779]

>>7576776
Don't walk, run.

[Anonymous No.7576796]

It's a linear functional which is just a name people have given to a certain kind of function.
You're an autist.

[Anonymous No.7576799]

>mfw that retard kid wastes 5 minutes of lecture time just to prove he's smart

[Anonymous No.7576800]

>>7576707
You saying it's a functional that returns the value an argument function takes at 0? Seems different from the wikipedia page.

>>7576706
>not technically a function
Can it be made one through nonstandard analytic framework, or is there no appropriate analog (considering either formalism or application/utility)?

[Anonymous No.7576810]

>mfw teaching a babby tier undergrad class
>Delta function comes up
>some slovenly guy in a Minecraft shirt corrects me and says it's not technically a function
>who_gives_a_fuck.png
>continue lecture
>he mumbles something under his breath for the rest of the lecture
>later see him in a hallway crying
true story

[Anonymous No.7577579]

>>7576705
I'd just like to interject for a moment. What you’re referring to as a the Dirac function, is in fact, a distribution, or as I’ve recently taken to calling it, Dirac distribution. The Dirac function is not an function unto itself, but rather another way of expressing a fully functioning limit of functions made useful by placing them in sequency
Many electrical engineers use a modified version of the Dirac distribution every day, without realizing it. Through a peculiar turn of events, the version of the Dirac distribution which is widely used today is often called the Dirac function, and many of its users are not aware that it is basically the a probability distribution, developed by Paul Dirac. There really is a type of delta, and there are people are using it, but it is just a discrete version of it
The Dirac function is a shorthand that you use to make you calculations easier. This shorthand is an essential part of electrical engineering, but useless by without a proper mathematical foundation; it can only function in the context of rigorous analysis .

[Anonymous No.7577582]

>>7577579
*sequence.

[Anonymous No.7577878]

>>7576765
Not irrelevant minutiae, it's an important definition. When infinite quantities pop up in physics and engineering they deserve careful treatment. All of the teachers I've had have gone into some amount of detail on what it is.

>>7577579
Good comment. Although I think it was developed before Dirac, he just invented the notation and made the concept more widespread.

[Anonymous No.7578011]

>>7577878
What class are you in? If it's circuit analysis 1 or 2, then he probably just told you to shut up because your signal analysis courses will discuss the fact that the impulse function isn't a "function" in more detail, and that for the purposes of the circuit analysis courses, it isn't really worth the time to delve into the details of what it really is.

[Anonymous No.7578033]

>>7578011
I'm not the OP, I'm a physics major and I have only learned about the Dirac Delta from a PDE class and an electrodynamics course I'm currently taking. Even if that is the case he could always say that it would be discussed later instead of insisting it was a function. Although I don't know how OP was acting, he could have been a dick about it.

[Anonymous No.7578043]

>that guy who only corrects notation and thumb errors
>He fails all of his examns

[Anonymous No.7578049]

Im starting a civil engineering course next year, are there any engineers in here that could please tell me what I should study up on before I start?

[Anonymous No.7578051]

>>7578049
City laws and baby maths

[Anonymous No.7578052]

>>7578033
You are going for master's in physics and you haven't been taught Dirac Delta in earlier years? What?

[Anonymous No.7578056]

>>7578051
T-Thanks anon.

[Anonymous No.7578063]

>>7578052
He is an undergrad who saw MIT open course

[Anonymous No.7578069]

>>7578052
>>7578063
What? I'm an undergrad, and I haven't seen any open course videos on the dirac delta.

[Anonymous No.7578071]

>>7578052
This does seem weird. I'm not sure how things are in the physics camp, but over in EE land, the impulse function is almost as ubiquitous as derivatives and integrals.

[Anonymous No.7578073]

>>7576705
You're an engineer. Why do you care?

[Anonymous No.7578127]

>>7576705
For babies it's a degenerated function (a limit of function series).
For dadies it's a distribution

[Anonymous No.7578132]

>>7578049
>what I should study up on before I start?
how to kiss ass.

[Anonymous No.7578156]

>>7578049
play around in a sand box

[Anonymous No.7578187]

>>7576707
<span class="math">\delta: C(R) \to R[/spoiler]

Takes (continuous) real-valued function to R, as defined in the post. What's the problem?

[Anonymous No.7578746]

>>7578069
TIL physics major = undergraduate physics

[Anonymous No.7578749]

It appears EE is baby tier math unless you go into the PhD level.

Still above CS though which is literally pre-fetal stage math :D,

[Anonymous No.7578816]

>the limit of a function is a function
no.jpg
<span class="math">\displaystyle \delta (x)=\lim_{\epsilon \rightarrow 0}\frac{1}{2\epsilon }e^{-|x|/\epsilon}[/spoiler]

[Anonymous No.7578829]

>>7578746
...yeah, most people major in something during undergrad. Sometimes it's physics. If I were doing a PhD I probably would have specified, but just because I left it ambiguous doesn't mean I'm doing a masters.

[Anonymous No.7579065]

>>7578829
I thought you get a Bachelor's after your 4 years or so of undergrad studies. Then you can go for a Master's and/or PhD.

[Anonymous No.7579100]

>>7578049

You should get as familiar as possible with Updog.

[Anonymous No.7579109]

>>7576707
made my day. i know engineers shit on mathematical subtlities even more than physicists do (since their daily work doesn't really require that much mathematical insight), but this is not even close to the heuristical definition.

[Anonymous No.7579114]

>>7576705
From wikipedia (https://en.wikipedia.org/wiki/Dirac_delta_function):

>In mathematics, the Dirac delta function, or δ function, is a generalized function, or distribution

What this tells me is that 'generalized function' is a synonym for 'distribution', and intuitively I'd claim that a generalized function is a type of function. Why is this not so?

[Anonymous No.7579117]

>>7576705
a good professor would have told you that the naming is just a convention that has historical roots.

[Anonymous No.7579120]

>>7579114
all strawberries are a kind of fruit but not all fruits are a kind of strawberry.
as the name indicates a generalized function is a broader/ more general term for certain mathematical objects that share characteristics with what we call a function but are not identical with them.

[Anonymous No.7579264]

>>7577579
>>7577878
you dont get it. its not dirac, its ganoo linux

[Anonymous No.7579271]

>>7577579
>tfw sci doesn't understand /g/ memes

[Anonymous No.7579277]

>>7576800
>You saying it's a functional that returns the value an argument function takes at 0?
According to Hans Feichtinger (who seems to know his shit as far as I can tell) it can be defined that way without running into any serious problems. Or at least he said he "prefers that definition" in a lecture I had that he taught.

[Anonymous No.7579279]

>>7579271
And there isn't a hope in hell of the converse happening either..

[Anonymous No.7579283]

>>7576776
>uses the term "Big Pharma" unironically during lecture
Honestly, depending on the context I can see that being somewhat legit. The pharmaceutical industry has considerable financial and lobbying means, and the interests of large pharma companies in terms of pending legislation and/or public opinion often overlap.

[Anonymous No.7579288]

>>7579100

[Anonymous No.7579291]

>>7576721
Are binaural beats not real? In what sense? I have definitely experienced the phenomenon personally. Maybe some crackpots claim a lot of pseudoscience mumbo-jumbo about binaural beats entraining your brainwaves or something. That's not real. But the "binaural beats" phenomenon itself is definitely real.

[Anonymous No.7579308]

>>7579291
Legit and real are two words with different meanings.

[Anonymous No.7579313]

>>7576705
The convention is to call it a function to fuck with mathematicians and autists

[Anonymous No.7579315]

>mfw professor emphasises that he's just teaching us the best model at the moment and we should think critically about everything

[Anonymous No.7579343]

>>7579313
But the terminology in physics (thus it extends to engineering too) is already as convoluted, misleading and ambivalent as possible; it's almost like it was made to confuse plebeians.

Why would you feel the need to do the same with mathematical terminology when plebeians have no chance of understanding any of it regardless of terminology (as opposed to physics)?

[Anonymous No.7580934]

>>7576705
It's a discreet function you fucking autists.

[Anonymous No.7580984]

>>7576810
Why was he crying ?

[Anonymous No.7582185]

I think you can treat it like a function and not run into any problems for the most part. Also, everyone just calls it a function.

I've noticed that ECE professors are a bit shaky on math/physics fundamentals. For example, one of my professors started calling voltage a vector, and repeated multiple times that the lines he was drawing were voltage vectors rather than electric field lines.