/sci/ - Science & Math

So, you wrote the wrong answer to a question and got fewer points for it. Sounds about right to me.

>>9762398
Bro the sigma has the same meaning as the calculus swoosh. I am summing up all the products of f(x) and the x differential from a to b. There is no need for a calculus swoosh there. My professor is being an asshole. For the last exam, he deducted one mark from every question where I didn't write a calculus swoosh. I ended up getting a C on the exam because of this autistic asshole.

>>9762405
Why don't you just get with the program and write the calculus swoosh you autist?

>>9762410
Because the calculus swoosh takes up two lines. When I am evaluating integrals, I use two to four times as much paper as for any other computation. Writing sigma is a perfectly valid alternative.

>>9762405
>sigma has the same meaning as the calculus swoosh

yes and no

>>9762405
>Bro the sigma has the same meaning as the calculus swoosh.
If you make the integral a riemann sum, changing every other variable and symbol to their riemann sum equivalents, you would be correct.

>>9762414
You (supposedly) study calculus at university - you can spend a few extra cents on paper when the need for it arises.

>>9762405
>Bro the sigma has the same meaning as the calculus swoosh.
No, it doesn't. It's analogous, which is why the integral sign is based on a stylized sigma, but it's not quite the same thing mathematically.

>I am summing up all the products of f(x) and the x differential from a to b.
Yeah, except that the x differential is not actually a number. Which makes this not *actually* a summation, but rather a symbolic trick that captures the ideal summation you would want but which doesn't actually exist. That distinction is very important, so it's important not to confuse them.

>For the last exam, he deducted one mark from every question where I didn't write a calculus swoosh.
Sounds about right.

I will teach my asshole professor a lesson. On the next exam I will write my calculus swooshes four or five times longer.

>>9762405
Hey man I feel you. I had my own notation set up in multivariable calculus a few years ago and the professor took off two points for each question, netting me a C as well. It was a midterm, and I got an A easy in the class still (those were the only marks he took from the midterm haha).

I say we rename the integral symbol "calculus swoosh"

>>9762423
Excuse me bro, but the differential is too a number - an infinitely small one.

>>9762439
Not in traditional calculus it ain't. There are alternative systems of calculus in which this is true, but OP presumably isn't studying those.

>>9762438
inb4 word filter

>>9762445
Calculus was literally founded on the idea of infinitely small quantities.

>>9762434
this would probably please him.
instead make it reeally small so it fits.

>>9762445
>There are alternative systems of calculus in which this is true, but OP presumably isn't studying those.
Which makes them untrue?
You sound like one of those faggots who cries when they need to know a formula that wasn't taught in class.

>>9762478
>faggots
Why the homophobia?

>>9762478
>Which makes them untrue?
No, it makes them irrelevant, because that is not what the exercise is talking about. The traditional integral and the nonstandard integral are different operations, written using the same symbol, and the same applies to differentials like dx. If you don't explicitly disambiguate your notation, they are assumed to refer to their standard meanings, in which case >>9762439 is simply incorrect.

>>9762414
Just fucking draw a swoosh that takes up one line. This is perfectly doable, see LaTeX inline notation. Alternatively, write the the LaTeX command for integral with the proper arguments, treating an integral like a function.

>>9762512
Make sure to get the / and $ and start equations right like a proper autismo. $/int_0^a fggot dx$.

>>9762512
>>9762525
And if you're integrating f(x)/g(x), you'd better write \frac{f(x)}{g(x)} inside as well. Can't use inconsistent notation.

>>9762393
> Lebesgue measure is the same as the counting measure.
Fucking derp.

>>9762414
>the calculus swoosh takes up two lines
Incorrect

>>9762414
>the calculus swoosh takes up two lines
how the fuck are you drawing the symbol? pretty much everyone I know and me does it in one quick stroke

>>9762580
>Implying OP who is a highschool edgelord overestimating his intelligence knows any measure theory.

>>9762434
I doubt he will care or notice.

>>9762393
>>9762405
>>9762414
>calculus swoosh
God damn, why are brainlets so entertaining.

>>9762405
>>9762437
When it comes down to grading, looks like adding a C is a constant!

>>9762405
>I ended up getting a C on the exam because of this autistic asshole.
You ended up getting a C because you ignore your teachers explanations and just do whatever you want.

>>9762434
If you really want to show him, write three swooshes for every one.

>>9763486
DAMMIT CARLOS

>>9763495
Bro, Barnett Calculus is graduate level math.

>>9762393
from the thread it seems you're doing it on purpose so you deserve it, but he should only deduct once in my opinnion

>calculus "swoosh"

>>9762405
>>9762414
Thanks for the laugh OP.

>prof deducts marks because I wrote an entire analytic proof of all rhombuses being parallelograms at the back page of my test paper
It clearly said "Prove that..." in the instructions, is my prof autistic?

>Prof deducts marks because I write in babylonian numerals

>>9762393
>using capital sigmas at all
>not using calculus swooshs over counting measures

>>9762414
Weird I have the opposite problem.

>>9762393
>>9762405
>>9762410
>>9762414
>>9762417
>>9762434
>>9762512
>>9763240
>>9763466
>>9764395

CALL IT BY ITS NAME REEEEEEEEEEEEEEEEEE

>>9762393
sigma is a discrete sum dude

>>9762393
This is obviously bait, but if you wanna represent a riemann-bordeoux integral using a sigma sign you need to use the limit.
As in: [eqn] \displaystyle \int_a^b f(x)dx = \lim_{n \rightarrow \infty} \sum_{i = 0}^\infty f(x_i^*) \Delta x_i^* = F(a) - F(b) [/eqn]
Now go kill yourself.

>>9762398
Well it's not exactly wrong to be fair. It's just really unconventional to write it like that. Prof probably figured OP was right on accident.

>>9764706
but then you'd have to define [math]x_i^*[/math] everytime you want to represent an integral

>>9764487
What do you mean?

In terms of importance, it's the difference between landing on the moon and landing on the sun, in the grand scheme of things.

>>9762393
a sum is not an integral get this straight faggot

>>9764464
lmao

>>9764847
props for effort, funny but not quite there

>>9762405
>Bro the sigma has the same meaning as the calculus swoosh.

No they dont.

>>9762405
The integral is a limit of Riemann sums. [math]\int f(x)dx = \lim\delta x\to 0 \sum_i \sup f(x_i) \delta x_i[/math] for a Riemann integrable function.

That limit may not exist as a sum. In fact, it doesn't exist as a sum for all function f where [math]f'(x)=0[/math] almost everywhere.

Grow up and take the hit. You'll learn more that way.

>>9764802
If your function is Riemann integrable then evenly divided partitions are fine, which is usually implied when no partition is specified.

>>9764802
Yes, thats why op is a retard (obvious troll).

>>9762405
This is bait but essentially if you didn't give take the limit on your riemann sum then you just gave an approximation of the correct answer (or a formula for an approximation if it was purely symbolic). There's no reason to do that when the integral was probably elementary and could just be solved with FTC

>Ph.D in Mathematics
>Specialized in triple calculus swooshes
>300k starting salary
>any job I want

>>9762405
>products of f(x) and the x differential
ahhahahhahahhahahhAHHAHAHHAHAHHAHHAHAHHAHAHHAHAHHAHAHAHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

>>9762405
> I ended up getting a C on the exam because of this autistic asshole.
HAHAHAHAAHAHAAHAAHAHAAH
this is fucking justice. If I was your TA I would have just zeroed you and forced a rewrite.

>2018
>not knowing the difference between summation and integration
You have some catching up to do.

>>9765909
>>9765910
>HAHAHAHAAHAHAAHAAHAHAAH
Mom let the hyaena use her computer again.