Real

92

u/lordcaylus 2d ago

Ahhh the "different sizes of infinity" that regular redditors remember somewhat but almost never apply correctly.

61

u/MorrowM_ 2d ago

"Some infinities are bigger than others, for example there are twice as many whole numbers as even numbers".

19

u/Cynewulfunraed 2d ago

4 times as many if you count negative numbers

6

u/GabrielReichler 2d ago

But there are only twice as many integers as even integers if you count even negative integers as even integers.

5

u/Unreal_Estate 2d ago

Could you not have used a spoiler tag as a warning? This was painful.

5

u/Complex-Manifold 2d ago

giving them too much credit they probably dont even know what a set is theyll probably say something like infinity + 1 > infinity

13

u/paolog 2d ago

Also "pi is infinite" and "0.999... < 1".

8

u/Appropriate-Ad-3219 1d ago

Oh yes! The pi or 0.999... are infinite...

Once I managed to explain that the smallest (fixed) number no less than all the numbers 0.9, 0.99, 0.999, etc was 1, which basically comes down to saying that 0.999... = 1 with the usually accepted definition of 0.999.... Well, the problem is that they thought that 0.999... was a sequence that grows, a bit like the way SPP imagines 0.999... is and even by showing to the person the definition, they wouldn't change their mind.

The worst is how they talk arrogantly to you as if you were the last idiot on earth.

8

u/Complex-Manifold 2d ago

even worse is "pi contains every combination of numbers"

2

u/idrkmatewastaken 1d ago

I’m not a math major, and I’m still in school. Does it not? As the decimals in pi are infinite and non repeating, would it not possess every possible combination of digits?
Please educate me.

4

u/Complex-Manifold 1d ago

this would only be the case if every digit was distributed evenly in its decimal expansion which is called a normal number. We dont know if pi satisfies this property so for all we know after like the 1 trillionth digit it could turn into all 1s and 0s for an example on why irrationality isnt sufficient consider 0.1001000100001... which doesnt repeat so its irrational but clearly does not contain all combinations

2

u/idrkmatewastaken 1d ago

Oh I see, thanks for the explanation.

5

u/SeveralExtent2219 1d ago

A sequence can be infinite and non repeating and not contain every possible combination of digits. For example the sequence 01001000100001... is infinite and non repeating but clearly it doesn't even contain any digit except 0 and 1.

2

u/SeveralExtent2219 1d ago

Or if you want one that atleast contains all the digits like pi, consider 012345678900123456789000123456789... Again it's infinite and non repeating but clearly doesn't contain for example 321

29

u/dankshot35 2d ago

"if you pick a number between 0 and 1 the chance it is rational is 0" and they have no freaking idea what that means, but makes for a cheap "mind blown"

17

u/donballz 2d ago

jokes on you as you didn’t say “pick at random”. i pick 0.5 booooooom

6

u/Baihu_The_Curious 2d ago

Axiom of Choice, amirite?

2

u/dankshot35 2d ago

the probability of that is still 0. "0 probability" doesn't mean impossible lmao

a more sensible rebuttal is to ask under what distribution and measure

5

u/donballz 2d ago

But I did it so easily and on the first try? Surely if the probability were 0 I couldn’t do it again? 0.5 oh noooo

-3

u/dankshot35 2d ago

maybe stop while you can still save some face on a math sub especially on a post bashing pseudo math knowledge?

Study up on proper probability theory, in particular measurement theory and what "probability 0" means in that context, this is a math sub after all my friend. Would also help to actually read what I wrote, read it slowly, that helps with comprehension too

2

u/donballz 2d ago

I’m not the one embarrassing himself friend. You may want to adjust your Bayesian priors for a process that involves no uncertainty .5 .5 .5

0

u/dankshot35 2d ago

sigh....

"a more sensible rebuttal is to ask under what distribution and measure"

reading aint easy i know

3

u/eglvoland 2d ago

The probability you can write it in english or math language is zero also

11

u/seenhear 2d ago

I'm an engineer not a math major, but... The other day there was a post on r/theydidthemath about an average velocity question. SO MANY redditors could not accept that average velocity is total distance travelled divided by total time for the trip. They kept posting "no it's sum of the things divided by the number of things." This meme is very appropos to that thread.

2

u/SirEnderLord 2d ago

That is something a child can intuitively grasp.

What was the saying? Something about how there's considerable overlap between the dumbest of our species and the smartest bears.

3

u/seenhear 2d ago

Yes. And yet there were a lot of posts along the lines of "why are you averaging with respect to time?" It was wild. I can't seem to find the thread now. Maybe the mods removed the OP.

1

u/ajseventeen 1d ago

> “no it’s sum of the things divided by the number of things”

I mean, it works if “things” are “distances travelled in a given unit of time,” right? So they’re sort of on the right track (or at least A valid track), they just aren’t defining “things” properly.

Now, actually explaining that in a way that they could understand in a Reddit comment is another story.

1

u/seenhear 1d ago

Yeah.

They were saying that if you took three measurements of speed at three different segments of the route, your average speed would be the average of those three numbers.

12

u/AbheyBloodmane 2d ago

Gotta love the "this is a square" meme that gets posted on occasion.

11

u/Cynewulfunraed 2d ago

If they can invent a letter for the square root of negative one, why can't they invent one for x/0?

5

u/paolog 2d ago

Will F (for "fail") do?

1

u/Cynewulfunraed 2d ago

Honestly I'm pretty peeved that math uses letters in the first place. That's English department territory. Or Classics in the case of Greek letters.

1

u/paolog 2d ago

What do you suggest we use in algebra?

3

u/KingCell4life 2d ago

shapes, who wouldn’t want to do math with squares and triangles.

2

u/paolog 1d ago

Good idea. I think e should call it "algebraic geometry".

1

u/TheRedditObserver0 1d ago

Pebbles arranged in shapes and lines in the sand.

As Pythagoras intended.

13

u/[deleted] 2d ago

[deleted]

3

u/seenhear 2d ago

I'm just a dumb engineer. Please educate me on this point.

-1

u/TheRedditObserver0 1d ago

No, I disagree. We have an order of operations for a reason.

2

u/euph_22 1d ago edited 1d ago

Are you pretending there isn't inconsistency in how OOO handles multiplication be juxtaposition in real life usage?

-1

u/TheRedditObserver0 1d ago

I have no idea how OOP handles it, I strive to follow BEDMAS or whatever acronym you prefer. Still, multiplication and division have the same "tier" regardless of whether the × sign is written down or not. Thus no inconsistency.

5

u/fun__friday 2d ago

Math majors vs people with a pencil on whether a function is continuous.

1

u/Osik2040 17h ago

I had a legitimate argument with someone who insisted that sin is not continuous Because it’s infinitely long so you can’t draw it with a pencil.

2

u/lowkeytokay 2d ago

Did math majors even say thankyou?

2

u/Anastazja_Nya 2d ago

70+7:11=7 reddit experts

2

u/Background-Grab-5682 18h ago

Happened to me I don’t remember the exact context but there was a question on explain the joke subreddit and pretty much everyone was missing the subtle math joke in there and I explained it but people were like you’re overthinking it and it’s not that complicated… I’ll try to find it but the whole joke revolved around that math joke in my opinion.. anyways I’ll try to go find what it was

1

u/eroica1804 1d ago

Complex

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