/sci/ - Science & Math

this is bait but you're a dumbass either way

>>11597014
prove it wrong. protip: you cant

>>11597010
yeah it works
multiplying by infinity has a side effect though
you lose definition in the real numbers

the issue is that
a*0 = 0
b*0 = 0

so dividing by zero you get:

a = 1
b = 1

any number becomes 1
you can see why that's an issue??

>>11597140
makes as much sense as 1 = 0.999...

>>11597151
exactly
both concepts involve infinities both big and small
which is why the math community had and still has a very hard time dealing with them

>>11597010
OP is a faggot, dividing by zero can be POSITIVE or NEGATIVE infinity.

>>11597010
0*inf is undefined

>>11597151
nope, not even close

>>11597169
You literally define infinity so that it is equal to negative infinity. Go to university, you moron.

>>11597170
you aren't evaluating 0 * infinity. it's just a middle point, like when you're dealing with the limit of a fraction with x in the denominator as x approaches to 0

>>11597186
middle point is undefined

>>11597182
>infinity so that it is equal to negative infinity
biggest mistake possible, well done

>>11597182
>left=right
>R=infinity
Shiggy diggy.

>>11597193
Fuck, you're dumb.
Look up the unit circle.

>>11597206
sorry, not asshole-oriented like your family

[eqn]Let \; x=0.999...[/eqn]
[eqn]∴10x=9.999...=(9+0.999...)=(9+x)[/eqn]
[eqn]∴9x=9[/eqn]
Just in case the topic comes up, you should know that no part of this proof is wrong.

>>11597258
It is.
>nooo you can't do operations with infinities
>does operations with never ending numbers
>assumes 0.9... times ten is 9.9...
This is one of the worst (non-)proofs of 0.9...=1

>>11597270
>assumes 0.9... times ten is 9.9...
That's ok. I'ts ok to assume something.
It just makes it a weak point in an otherwise flawless proof.
Now all you need to do is show the assumption is wrong.
>makes popcorn, waits

>>11597270
>assumes 0.9... times ten is 9.9...
That's ok. It's ok to assume something.
It just makes it a weak point in an otherwise flawless proof.
Now all you need to do is show the assumption is wrong.
>makes popcorn, waits

>>11597140
Not really. You're converting infinity to a finite representation, which by the nature of infinity isn't possible, so instead you just have a binary. You're either at 0, or non-zero, which means you're somewhere on your way to infinity, aka you are part of inifnity. 0 = 0, 1= infinity. The "uncountable" infinity between 0 and 1 becomes the same as the countable infinity of numbers.
I'm not sure what issues this results in, as now you've got a countable set mapped onto an uncountable one. But thats where this leads. and it makes sense

>>11597270
>its ok to assume something
>you need to show the assumption is wrong
>>leee makes popcorn like a b0ss
I assume you have no better than HS math knowledge, but most importantly I assume you have to RETURN TO >>>/LEDDIT/

>>11597258
what does the predator symbol mean?

>>11597010
>move infinity to the other side

>>11597309
You're the one providing the proof, so you prove it dumbass. You basically need to prove that algebraic operations work with convergent sequences, and that 0.999... exists. Your "proof" is shit

>>11597342
stop whining, snowflake
and do the work

>>11597424
>Your "proof" is shit
so disprove it then, should be easy

>>11597429
There's obviously no way to disprove what you wrote. That doesn't make it a good or even a remotely valid "proof".

>>11597432
He cannot disprove the claim, obviously. He pointed out the flaw in the proof, hence it is not valid, and is just nonsense.
Here's one: Prove that 1>0:
Well the letter "t" occurs in this sentence, so 1 must be larger than 0.
You can't disprove my claim, so according to your logic, the proof must be good and valid..

>>11597432
Theres nothing to disprove. You didn't prove anything

>>11597434
>no way to disprove
ok then, I agree

>>11597455
A good, so you see that what you wrote is complete nonsense, and you should stop posting it in these threads, and let people who are actually capable of math talk.

>>11597010
but x/inf isn't 0 retard it approaches 0 when you take the limit of x/y as y->inf

>>11597458
nah, >>11597258 is good.
you lose

>>11597443
>Prove that 1>0:
wake up idiot, you were asked to disprove the assumption
your weird rant is totally irrelevant

>>11597509
Prove the Riemann hypothesis:
Assume the Riemann hypothesis is true. Hence, the Riemann hypothesis holds, and the proof is complete.
Where is my Field's medal? No one can disprove my assumption, so the proof must be valid.

>>11597521
yeah, this isn't the RH.
concentrate.

>>11597562
Learn basic logic.

>>11597564
If A is ok then B is ok
doesn't get more basic than that
now disprove A

>>11597010
A number divided by infinity is technically not zero, but it is infinitesimally small. So in this case, you create infinity by doing the reverse, dividing x by an infinitely small number.

>>11597648
>infinitesimally small
in R that's zero

Genius

Why can't we divide zero by zero?
Isn't it one?

>>11597710
lim_x-->0 2x/x = 2
guess not

>>11597010
this is a common convention e.g. in complex analysis. what's your point ?

>>11597623
Yes, if Riemann hypothesis is okay, then Riemann hypothesis is okay.
Doesn't get more basic than that.
Now disprove Riemann hypothesis.

>>11597010
[eqn]
\frac{x}{-\infty} = 0 \\
x = 0 \cdot (- \infty) \\
\frac{x}{0} = -\infty
[/eqn]

>>11598369
You forgot to multiply by -1 first, then 0=-0 and continue as above.

>>11598293
>hand waving, delaying
just do it anon >>11597258

>>11598369
>>11597170

>>11597010
it is actually correct,
[math]\frac{x}{\infty} = \pm \infty[/math]

If you have looked at the graph once in your life you would know. End of the discussion. Thanks.

>>11597010
>a number divided by infinity = 0
> x / oo = 0
true, if you exclude x=0

>move infinity to the other side
> x = 0 * oo
hmm no
if x=1 then 1 = 0 * oo
if x=2 then 2 = 0 * oo
therefore 1 = 2 which is a contradiction
thus moving infinity to the other side is an invalid move

>move 0 to the other side
> x / 0 = oo
as step 2 leads to a contradiction, step 3 can be ignored

>>11598447
x/inf = 0 sweetie

>>11598447
>>11598578
yes, thanks, it's a typo. I meant to write x/0

>>11598434
Just do what? I'm pointing out the logical flaw.

>>11598658
stop dragging your feet and say something concrete

>>11598676
Irony is lost on you then, given none of what you've said is concrete... or even coherent. Here is my point:
Your so called "proof" is flawed, and essentially assumes the result from an actual proof of why 0.999...=1. So stop posting it on all of these boards, and learn logic so you can stop embarrassing yourself.

>>11598447
nah fuck off mate, the strongest statement you can make (that is actually true) is [eqn]
\lim_{x\to\infty^\pm} = \pm \infty
[/eqn] iff [math]x\neq0[/eqn]

>>11598703
*
[eqn]
\lim_{y\to0^\pm} \frac{x}{y}= \pm \infty
[/eqn]
if [math]y>0[/math]

>>11598688
>something concrete
line by line ? try it big boi

>>11598714
>.....if y>0
kek, kind of hard to do the 0- approach then

>>11598767
Yeah sorry I fucked up, I actually meant to write
[eqn]
\lim_{x\to0^\pm} \frac{1}{x} = \pm \infty
[/eqn] but after messing up twice I thought fate had decided it wasn't to be.

>>11597010
>"why yes, .999...=1 obviously"
>"NOOOOOOO you can't just use infinity to do maths!!!"
Real Anal homosexuals on suicide watch.

>>11598813
You can use the extended reals to do maths, as long as you forgo many of the properties of the real numbers such as cancellation
Regardless, proof 0.999... = 1 doesn't rely on the extended reals and can be done using cauchy sequences or dedekind cuts

>>11598813
>I'm too stupid to understand why operations with infinity sometimes work or sometimes don't, so instead of ACTUALLY LEARNING some damn math I'll make a wojak meme mocking THEM for MY lack of understanding.
Totally got us bro...

>>11598896
>NOOOO you can't just use wojak memes, don't mock meeee

>>11597158
>the math community
No, just the retards

>>11597140
>a*0 = 0
>b*0 = 0
there needs to be a nonreal null number of magnitude "a" for a*0 to be bijective

>>11597158
>there is infinity and there is infinitely small in both problems
>therefore they are the same
fucking kill yourself

>>11597010
https://en.wikipedia.org/wiki/Extended_real_number_line
https://en.wikipedia.org/wiki/Projectively_extended_real_line

These should answer all questions.

>>11598783
so 1/0 isn't equal to infinity, but is approaching it. so why did "hurr durr divide by zero" become a meme when it's no different than any other irrational number (like pi)?

>>11597010
dude I think even high-schoolers would have recognized this basic pattern(limit as x approaches 0 for 1/x), I don't think this has any rigorous meaning though.

>>11597346
Therefore, retard. Learnt that when I was 12

>>11600518
No need to be rude.

>>11600552
it's a predator sign, what did you expect
shitstain retard

>>11597010
What's infinity divided by infinity though

>>11599138
It's sad that all the retards in this thread seem to have ignored this.

>>11600625
inf/inf is undefined

>>11600625
infinity

Why does math have many undefined things?
What kind of things can we define?

>>11601106
whatever you want
it's just that if you define too much, your definitions will contradict each other
A collective set of assumptions and definitions form a mathematical theory, that theory's assumptions and deifinitons have logical consequences that are always true where their assumptions and definitons are true. these are known as theorems and lemmas

mathematics, as a whole, is inconsistent and has no universal assumptions or definitions. high level math is more about the abstract studying of assumptions and the logical conclusions they lead to, this is known as inductive reasoning.
reverse math is an interesting field btw as a side note. you work backwards. you see some properties, or some structure, and ask "what assumptions and definitions not only allow for this structure/property, but give rise to it". It's a surprisingly difficult field. It's also the only mathematical field to my knowledge that is more-so deductive than inductive.

>>11597010
This is unironically true in the Riemann sphere. Even that simple stuff is way above the /sci/ paygrade though. It's clear /sci/ is full of highschoolers/high school dropouts. The torrent of absolute shit just keeps flowing.

>>11601283
*pedantic correction: Top and bottom are true in the Riemann sphere assuming [math]x \in \mathbb{R}[/math].

Any number divided by negative infinity is also 0. Therefore moving negative and 0, any number divided by 0 is negative infinity. Then negative infinity is positive infinity.

>>11601353
>negative infinity is positive infinity
bullshit
inf+inf=inf
inf+(-inf) is undefined

>>11601369
So what retard what are you trying to accomplish by these ramblings?

>>11601380
it's called math, you should try it sometimes

>>11600644
This

lmao infinity isn't even a number and has no rational relationship with numbers. It is as ethereal and enigmatic as god.

stick to hard real numbers, mathlets.

>>11601483
inf-1=inf
1/inf=0
cope

>>11601490
prove it, faggott

>>11601495
just feed them into WA

>>11601568
WA can't even handle big normal finite numbers, much less Large numbers. Why the fuck would you think it can handle infinity?

https://www.wolframalpha.com/input/?i=is+infinity+a+number%3F

>>11601573
lol
cope

>>11597010
>elementary algebra

this is why you attempt to solve equation using infinity as an integer

>>11601490
[eqn]\infty - 1 = \infty\\
\infty = \infty + 1\\
\infty - \infty = 1\\
0 = 1[/eqn]

>>11602522
so it has the same skrewyness 0 does with multiplication
[math]0\div1=0[/math]
[math]0=0\cdot 1[/math]
[math]0\div 0=1[/math]
[math]\infty=1[/math]
that just means you need to be careful with it
not that it's invalid
the weird shit that arises with infinity isn't why it isn't included, in fact some systems do include it. It isn't typically included since it simply isn't a number, it does not describe a quantity, but rather it symbolizes something greater than any quantity. you could argue 0, negatives, and i are similar in that regard, but i simply works out too cleanly to ignore and 0 allows addition to have an identity which makes it useful. negative numbers model lacking amounts, which are useful to capture

>>11602522
[math]\infty-1[/math] and [math]\infty+1[/math] are irreducible

>>11602522
inf-inf is undefined

>>11602569
0/0 is undefined
inf>1

>>11602630
infinity > 0

>>11602630
>0/0 is undefined
so is
[math]\infty -\infty[/math]
both can be manipulated to make any number seem reasonable as an answer

inf/inf = 1
inf*1 = inf
inf*2=inf
inf/inf = 1
inf/inf = 2
inf/inf = 1 = 2
1 = 2

>>11603530
>inf*1 = inf
>inf*2=inf
inf*1 is not reducible
inf*2 is not reducible

>>11603530
inf/inf is undefined

>>11597010
infinity isn't a number

infinity is measurably smaller than Large numbers. Meaning trying to increment to infinity from 1 per planck time between the beginning of the universe to the end of the universe would eventually end when the universe does. However a Large number would have still not been incremented to by that time.

infinity is a philosophical concept, not a mathematical one. it has no reasonable utility or definition relative to numbers. Even Large numbers don't.

>>11603684
It is a cardinal number, but not a member of the Reals.

>>11597151
Wrong, retard. "1=.9..." makes sense because we can actually prove it (pic related).
>>11597258
Actually it is wrong, but the conclusion is correct. Use pic instead.

>>11598574
>therefore 1 = 2 which is a contradiction
no, it's not.
OP's operation is proof that binary is the only valid mathematics.
Trust me, I'm a Doctor after all

Pic related is how the extended reals are defined. It is important to remember that all this is just convention and that THE REALS ARE NOT THE SAME AS THE EXTENDED REALS.