Spyke
aussie.zone

Fake and gay.

No way the engineer corrects the mathematician for using j instead of i.

292
LeFrogreply
discuss.tchncs.de

As an engineer I fully agree. Engineers¹ aren't even able to do basic arithmetics. I even cannot count to 10.

¹ Except maybe Electrical engineers. They seem to be quite smart.

52
boonhetreply
sopuli.xyz

Engineer here, I can definitely count to 10 tho

0 1 10

46
gnutrinoreply
programming.dev

Electrical engineers are the ones that use j though (because i is used for current)

32
lemmy.dbzer0.com

Except maybe Electrical engineers.

Yup, I can count just fine to the 10th number in a zero-indexed counting system: black, brown, red, orange, yellow, green, blue, violet, gray, white.

9

The inner machinations of an electrical engineer is too complicated for me to understand, I think they might be thinking on a higher order to understand these circuits

Thats why I barely passed my electrical engineering class lol

5

Having worked with electrical engineers, some of them are quite smart, the rest have lead poisoning.

5
Hoimoreply
ani.social

How do we know it's gay though? OP could be a girl (male)

39

Because it's 4chan. And there are no women on the Internet on 4chan

58

Right? They got that shit backwards. Op is a fraud. i is used in pure math, j is used in engineering.

20
Kogasareply
programming.dev

The mathematician also used "operative" instead of, uh, something else, and "associative" instead of "commutative"

20
Zagorathreply
aussie.zone

"operative" instead of, uh, something else

I think they meant "operand". As in, in the way dy/dx can sometimes be treated as a fraction and dx treated as a value.

3
Zagorathreply
aussie.zone

The operand is the target of an operator

Correct. Thus, dx is an operand. It's a thing by which you multiply the rest of the equation (or, in the case of dy/dx, by which you divide the dy).

2
Zagorathreply
aussie.zone

You're misunderstanding the post. Yes, the reality of maths is that the integral is an operator. But the post talks about how "dx can be treated as an [operand]". And this is true, in many (but not all) circumstances.

∫(dy/dx)dx = ∫dy = y

Or the chain rule:

(dz/dy)(dy/dx) = dz/dx

In both of these cases, dx or dy behave like operands, since we can "cancel" them through division. This isn't rigorous maths, but it's a frequently-useful shorthand.

1

I do understand it differently, but I don't think I misunderstood. I think what they meant is the physicist notation I'm (as a physicist) all too familiar with:

∫ f(x) dx = ∫ dx f(x)

In this case, because f(x) is the operand and ∫ dx the operator, it's still uniquely defined.

2
lemmy.world

That part also got me really confused. All the mathematicans I know use i while engineers use i or j depending on the kind of engineer. I've never seen a Pikachu engineer using anything other than j.

66

Pikachu engineer

That's a fucking favorite now. Keeping that in my back pocket.

24

OPs boyfriend is obviously an i engineer and hates j engineers. No one can stay angry at mathematicians - engineers on the other hand...

3
Jarixreply
lemmy.world

I clicked your link, I barely made it out of highschool so I have no idea what any of it means, but I like reading things I shouldn't understand anyway, sometines it's so interesting even without understanding.

So I thank you!

5

Quaternions are the closest we get to lovecraftian horror in real life.

Four dimensional and mostly imaginary, they were carved into a stone bridge by a crazy mathematician in a fit of madness, Lord Kelvin called them "unmixed evil", and the Mad Hatter from Alice may have been inspired by them.

Also they have been a curiosity at best for a long time, despite the efforts of a secret Quaternion Society, but they suddenly blew up in usefulness in modern times as they happen to be an easy and fast way for computers to describe rotations in 3D space, so they're everywhere.

Yeah, lovecraftian as shit.

3
lemmy.dbzer0.com

It gets worse actually. You can define a number system using any power of 2 amount of i-like units in a similar relationship to quaternions using the Cayley-Dickson construction

Fascinatingly, you lose some property of the algebra at each step. Quaternions aren't commutative: ABC != CBA. Octonians aren't associative: (AB)C != A(BC). Once you get into 16 i's with subscripts, it really gets crazy.

(Also, I just got the joke. Damnit @[email protected] your serious answer threw me off!)

14

I agree. Clearly i is current. What is this i=√-1 nonsense.

12

[Lapsed] mechanical engineering gang checking in. I was also surprised. Though, tbh, I think it came down to personal preference of the professor more than field-wide consensus.

6

Thado-mathocist. The real chad all along.

It makes me wonder if somewhere out there in a multiverse, a community of lisping incels all collectively draw the chad wojak as as an aramaic looking dude.

0

I’m a mechanical engineering student with a math minor and I’m a switch so yeah, I’d take either side of this

26

Something something distance calls for norm, not just squares.

||i||² + ||1||² = 2

15

Imagining your death. :P

But seriously, it's perfectly sensible when remember that i is just the mathematical representation of "left turn", just like -1 is the mathematical representation of "go backwards"-- and as we know, two left turns sends you backwards. So think about this triangle in the following way:

Imagine you are a snail, starting at the origin. Now imagine that you walk forward 1 step along the horizontal line. Then you turn 90° to the left to start walking along the vertical line, but then, because you need to walk i steps along this line you take another 90° turn to the left, which means that you are now walking backwards and you end up back at the origin. How far away from the origin are you? Zero steps.

6
lemmy.world

operative?

Also mathematicians use i for imaginary, engineers use j. The story does not add up. I have never seen a single mathematician use j for imaginary.

57
sartalonreply
lemmy.world

As an EE, I used both. Def not a mathematician though. Fuck that, I just plug variables into programs now.

9
lemmy.world

Engineer here: mostly use i, but have seen j used plenty. First time I saw j used was by a maths professor.

3

Interesting I never saw j from a maths person. Friends (from a decade ago!) in electronics eng dep said they use j because i was reserved for current. perhaps the latter depends on the department.

6

Webdev not knowing anything about computer science (and thus mathematics)? I am shocked. Shocked!

4

I have no idea what they're talking about, but I do love a happy ending.

30
lemmy.today

As a physicist I can't understand why would anyone complain about a +jb or $\int dx f(x)$. Probably because we don't fuck

29
lemmynsfw.com

As a software dude I can see you wrote a regex, I just can't find out what you're trying to match.

21
lemmy.world

Pardon my denseness, but is this sarcasm? Since that is a TeX snippet.

Why would a RegEx start with a $?

4
cub Guccireply
lemmy.today

Heeyy... So when you need to express something more, well, delicate than just code, you need to use math symbols. For that you can use tex expressions. Modern markdown supports it: just copy and paste the $..$ part into any render engine

3

Nooo... You should write spec and generate code, not the other way around

2
lemmy.world

Why would a mathematician use j for imaginary numbers and why would engineer be mad at them?

25
lemmy.world

The only thing I can think of is that the OP studied electrical engineering at some point. But it's a 4chan story so probably fake anyway.

23

I think it might be the wrong way around: Engineers like to use j for imaginary numbers because i is needed for current.

10

Mathematicians are taught to be elastic with notation, because they tend to be taught many different interpretations of the same theory.

On the other hand engineers use more strict and consistent notation, their classes have a more practical approach.

Using the same notation makes it faster to read and apply math, a more agile approach helps with learning new theories and approaches and with being creative.

8
lemmy.world

I think rather d/dx is the operator. You apply it to an expression to bind free occurrences of x in that expression. For example, dx²/dx is best understood as d/dx (x²). The notation would be clear if you implement calculus in a program.

23

If you use exterior calculus notation, with d = exterior derivative, everything makes so much more sense

2

I just think of the definition of a derivative.

d is just an infinitesimally small delta. So dy/dx is literally just lim (∆ -> 0) ∆y/∆x. which is the same as lim (x_1 -> x_0) [f(x_0) - f(x_1)] / [x_0 - x_1].

Note: ∆ -> 0 isn't standard notation. But writing ∆x -> 0 requires another step of thinking: y = f(x) therefore ∆y = ∆f(x) = f(x + ∆x) - f(x) so you only need ∆x approaching zero. But I prefer thinking d = lim (∆ -> 0) ∆.

4

But the post says before the integral, so I understand what they did would be $dx \int f(x)$, which is disgusting

2
slrpnk.net

Integrals are an expression that basically has an opening symbol, and an operation that is written at the end of it that is used also as a closing symbol, looks kinda like:$ {some function of x} dx.

The person basically said "the dx part can be written at the start also, and that would make my so mad :3": $ dx {some function of x}.

This gets their so mad because understandably this makes the notation non-standard and harder to read, also you'd have to use parentheses if the expression doesn't just end at the function.

Note: dollar used instead of integral symbol

10

I also use dollars instead of integral symbols, I don't do math though.

2

An integral is usually written like ∫ f(x) dx or alternatively as df(x)/dx. Please note that this is just a way to apply the operation 'Integration', like + applies the operation 'Addition'. There is no real multiplication or division.

But sometimes you can take a shortcut and treat dx as a multiplied constant. This is technically not correct, but under the right circumstances lands you at the same solution as the proper way. This then looks like this ∫ f(y) dy/dx dx = ∫ f(y) dy

Another thing you can do is to move multiplicative constants from inside the Integral to in front of the Integral: ∫ 2f(x) dx = 2 ∫ f(x) dx. (That is always correct btw)

What anon did was combine those two things and basically write ∫ f(x) dx = dx ∫ f(x). Which is nonsensical, but given the above rules not easily disproven.

This is more or less the same tactic used by internet trolls just in a mathy way. Purposefully misinterpreting arguments and information, that cost the other party considerably more energy to discover and rebut. Hence the hate fuck.

6
lemmy.world

Hum... I don't think the integral "operator" applies by multiplication.

You can put the dx at the beginning of the integral, but not before it.

9

Nobody on your link is treating the integral "operator" as multiplicative.

dx \int f(x) is blatantly different from \int f(x) dx

4
lemmy.world

If you were using nonstandard analysis with dx an infinitesimal you could put it outside I guess. Maybe with differential forms too?

1
marcosreply
lemmy.world

Switch it with a summation operator and see if it makes sense. The problem isn't the operation by itself, but the fact that the operator implies an argument application, like a function.

3

In the case of dx as an infinitesimal it makes sense. You are making a sum of all the values of the function in the integral range and multiplying with a constant dx.

1

In the context of differential forms, an integral expression isn't complete without an integral symbol and a differential form to be integrated.

2
Jarixreply
lemmy.world

Imagine a top that isn't math brained, giving you so much more opportunities to troll before they find out...and then when they do learn something you have been trolling them....

0
djsoren19reply
lemmy.blahaj.zone

No, in my experience people like that just end up trolling me because they have no frame of reference and don't care about reality. You can't troll somebody with math if they reject the idea of learning anything about or using math.

3

I can see that.

I did mean someone not learned already, not someone that doesn't care to learn but I will concede the point now that you pointed out the flaws

if you have more opportunities to troll, then that's also more room for disappointment as well, I guess I was thinking in terms of intensity more than opportunities. Thanks

3

My initial thought was that it's surprising that the engineer is using i whereas the mathematician is using j. But I know some engineers who are hardcore in favour of i. No mathematicians who prefer j though. So if such an engineer were dating a mathematician of all people who used j, I could see that being ♠ .

1

Hate ****

I too take hate shits on the toilet.

0
lemmy.world

so after he angered his bf he got fucked as in trouble with him or sex? raped? wtf lol

-4
jylreply
sopuli.xyz

Wtf mate, nothing that serious. Anon teased him and the score was settled when they did the thing later that night.

The story looks pretty fake and gay anyway, but it's more wholesome than your idea.

14

hate fuck:

An act of aggressive sex with someone as if they had no respect for the person as an equal human being, regardless if they actually do, or not. Hate fucking usually entails aggressive, sometimes violent, degrading, and humiliating sexual acts and behaviors perpetrated by an aggressive party onto a submissive, solely in the interest of the aggressor's own pleasure and amusement, and without regard for the submissive party's enjoyment or well being.

Unlike rape, hate fucking is a form of consensual sex where the submissive party has agreed (for whatever reason) to accept the treatment and behavior of the aggressor.

Though unlike proper BDSM, the submissive party has not previously discussed boundaries, likes or dislikes, and doesn't necessarily enjoy all, or even any of the treatment they receive.

https://www.urbandictionary.com/define.php?term=hate+fuck

7
Shayetareply
feddit.org

Didn't realize you had to be a nazi in order to post on 4chan.

8
ayyyreply
sh.itjust.works

If you are unaware of 4chan being a tool to push people towards fascism, you seriously need to do some more reading and learning. It is an explicit goal of the platform. Here is a random example of an article you can read. Wikipedia is also full of good information.

-2
Shayetareply
feddit.org

"Revealing the discordian 4chan sub-groups actively fighting FOR oppression of basic human rights the the differently-abled."

Ah, so its no longer the entire site, but a sub-group of users.

Listen, the site itself is neutral, anyone is free to post anything they want. The only actual rule is to not post anything illegal.

1
Leesireply
lemmy.blahaj.zone

Technically true yeah. But I frequented 4chan in the old days. It is not the same website by a long shot. Yes, it has always sucked, but now it's even worse somehow.

Like most other social media, I'd bet good money that there are astroturfing campaigns running trying to radicalize the those who browse there, especially since it's easier to introduce divisive messaging as edgy humor.

Probably a higher success rate than most other social media considering the shit you see on /pol/ and likelihood of harboring incels and other ideologically susceptible users.

2

Agreed, I wouldn't be surprised if 70% of posters on /pol/ were goverment employees/automated systems of various countries each pushing their own propaganda. This is true of other boards as well, but /pol/ is hardly an accurate representation.

It is unfortunate that the one place on the internet where you can voice opinions fully anonymously has fallen so much.

2
Match!!reply
pawb.social

4chan is a largely fascist website but that doesn't mean every single screenshot is fascist or does something to promote it

8
ayyyreply
sh.itjust.works

It normalizes their behavior instead of shunning it. Remember: If there’s one Nazi at the bar who hasn’t been kicked out, you’re at a Nazi bar.

-3

There is a nazi at the bar (4chan) but also there's a gay couple at the bar (the OOP). the gay couple leaves that bar and goes to another bar (Lemmy). is the second bar and its bargoers now also Nazis?

8
Dutczarreply
sopuli.xyz

Doesn't Lemmy have a ton of tankies on some instances?

If it's fine because it's a different instance, doesn't that apply to different 4chan boards?

1

This was the reply that really made me think twice about my position.

2