Is 1 = 0.999... ? Really?

And still can’t get it right. I’m impressed.

So you consider yourself a mathematician?
Mr Donald Trump considers himself a US President.
Your point?

What you appear to NOT be is an adequate logician for resolving questionable issues. Memorizing maths formulas does little in that regard and I’m sure actually diminishes the necessary talent.

And this is just why I don’t consider your opinion to be valid on whether I got some maths right.

This wishful thinking that “knowing the math” and “being able to resolve questionable issues” is some kind of trade-off is simply often not the case, to which the countless mathematical innovators at the very top levels can attest by virtue of their breakthrough accomplishments. In many cases, memorisation alone isn’t enough of course, but that isn’t enough to let you off the hook for not knowing/memorising maths formulas. Consider Terry Tao, “regarded by many people as the world’s greatest mathematician”, who will openly talk about how learning tricks and formulae makes all the difference when it comes to resolving questionable issues. That’s the reality, and it’s the Trumps of the mathematical world who merely think they can innovate where far greater minds have failed before, like you/JSS and Magnus are/were doing. I’m just relaying what the greater minds say, and I’m not saying I’m up there with them, just that I’m further up than the Dunning-Kruger effect will allow some people to accept.

Look, if you both really can’t accept that I’m right, forget I said anything at all and listen to all the many professional mathematicians who are saying the same thing. I’m not here, ok? I’m just a messenger. Listen to the people who are actually highly capable in this field, and by all means be skeptical of them to some constructive degree, but have the humility to accept that in all likelihood you don’t have what it takes to legitimately challenge the heights that high-level professionals are operating on. I’m sure some amateurs exist who actually can come out of nowhere to succeed in such a task, but in all probability that’s not you - as always: the more you learn about something, the more you appreciate just how out of your reach it actually probably is. It’s obvious to me that neither of you have been through that and come out the other side - on this topic whole topic at least - but like I said, don’t take my word for it. I might be a mathematician but I’m not a professional, so if you resent me for being straight with you, go straight to consulting the top instead of going through me.

Not really. There’s a big difference between the two.

I merely asked him what’s the purpose of talking about the standard algorithm of adding numbers together (which, by the way, is not the same as addition.)

First of all, I wasn’t talking about addition in general (a distinct concept), I was talking about the standard algorithm of adding numbers together. This isn’t the same as addition.

And I didn’t admit that one cannot use standard algorithm of addition to find the sum of (0.\dot0{1}) to (9.\dot9). I merely asked a hypothetical question.

There is a difference between the two numbers and there’s a super simple proof for it. If it’s the case that this proof is a real proof, which I firmly believe that it is, nothing else is relevant. Don’t think you’ve presented a single argument against it.

The word “finite” and the word “infinite” are opposites but the word “finite quantity” and the word “infinite quantity” have a lot in common given that both are quantities.

Not quite. Not when it comes to this subject.

There are no obvious arguments.

Not quite.

You have no clue what you’re talking about, so maybe you should just stop it and instead stick to the topic, what do you think?

Instead of talking about who you are and how many people agree with you, how about you show us the flaws in our arguments? But without pretending that you did. Whatever you did wasn’t enough. Accept it and either leave the thread or continue discussion.

Show people where they are wrong, don’t tell them that they are wrong. And if you can’t be bothered, because you estimated that it’d take too much effort, leave. Everything else is an expression of frustration with the fact that people aren’t agreeing with you (“Oh why can’t people accept what the Great Wise Man Silhouette has to say on the subject!?”) As if people are supposed to behave according to the expectations of the Great Wise Silhouette (or anyone else.)

Consider that, in practice, it might happen to be useful to be mistaken on this subject. I’m not saying that it is, but let’s assume that it is. What would be the correct answer to the question posed in the OP? Would you say (1 = 0.\dot9) or would you say (1 \neq 0.\dot9)? For (1 = 0.\dot9) is more useful in practice whereas (1 \neq 0.\dot9) is more logical. If the subject of this thread is what is useful, the correct answer would have to be (1 = 0.\dot9). But I’m insisting that’s not the subject of this thread. This thread is primarily about what is true.

:laughing: This is hilarious - you’re consulting “Math for Kids” as the source to share your level of knowledge!

You’re talking to someone who casually came up with their own original algorithm for addition (and other arithmetical operators) based on binary logical operators alone over 6 years ago.

The standard algorithm of adding numbers together is addition. I can’t believe I’m having to repeatedly state a tautology for you. That is, it’s a system of adding digits when numbers with more than 1 digit are involved. There’s other algorithms that do the same thing, such as the one I invented myself - and guess what. They’re all addition! #-o

You keep insisting that my explanations are merely “telling you” rather than “showing you”, and here you are simply making claims without explanation:

Mere claims. No explanation. Right there in front of us.

By contrast, you even quoted one of my explanations on the last page.

So opposites have a lot in common when they qualify the same concept.
“They have in common” the concept that they’re qualifying only, opposites don’t suddenly have a lot in common just because they’re referring to the same thing.
“A and ¬A have a lot in common because ∃(A ⊂ B) ∧ ∃(¬A ⊂ B)”… :confused:
^this is an explanation of your logical error that you’ll proceed to deny exists.

  1. Argumentum ad populam: a fallacious argument that concludes that a proposition must be true because many or most people believe it.
  2. affirming the consequent: a formal fallacy of taking a true conditional statement invalidly inferring its converse even though the converse may not be true.
  3. False Dilemma: a type of informal fallacy in which something is falsely claimed to be an “either/or” situation, when in fact there is at least one additional option.

You said: “Perhaps because some of us are interested in what is logical rather than what is popular?”
Let:
(P) denote “popular”
(Q) denote “logical”
In the above quote of yours you imply that I commit 1): (P\rightarrow{Q})
“Logical rather than what is popular” takes the form of 3): (P\lor{Q}, Q\vdash\lnot{P})
Combining 3) with a rejection of 1) takes the form of 2): ((\lnot(P\rightarrow{Q}),Q)\vdash\lnot{P})

Quite obviously I know what I’m talking about, so maybe you should just stop insisting I don’t, what do you think?
I keep showing you the flaws in your arguments, but it’s never enough, nor does it even count as showing apparently, just “telling”. This fallacy that you’re commiting is called Moving the goalposts such that no amount of explanation that I offer ever counts as explanation.
I expect people to respond to my clear logic, and of course I get frustrated when you keep just coming back with “nah, didn’t happen, you just don’t understand”. I expect people to exhibit cognitive biases and to encounter the backfire effect, but what I’m encountering here just seems like complete and utter dumbness.

Stubborn as a mule.

That’s correct.

When we say “The number of people on planet A is less than the number of people on planet B” it does not mean that we can “finish counting” the number of people on either planet.

I’ve demonstrated this before. If you have a planet populated by an infinite number of organism, and you remove one organism from it, you’d have fewer organisms, even though you can never “finish counting” the number of organism on that planet.

By definition, if you have a bunch of things in one place (regardless of their number) and you subtract one thing, you get a smaller number of things. To say otherwise is to say that you didn’t really perform the operation of subtraction, which is a logical contradiction.

Not quite.

You’d get confusion.

This thread is about concepts.

Yes, really.

Why are infinite quantities not quantities?

Your (n) is a symbol representing an unknown. (1cm) is not representing an unknown. You’re comparing a known value ((1cm)) to an unknown number ((n)) of gwackometers.

Not sure why any of this is relevant, to be honest.

Of course I do.

I am “on my own”. That’s a good argument.

Because Gib says so. Again, no arguments whatsoever. You are merely declaring that infinite quantity isn’t really a quantity.

I am certainly not saying that the reason (\infty) represents quantity is because you can plug it into a mathematical equation.

That would be your misunderstanding.

I am saying that every unit can be represented as a number of other, smaller, units. For example, (m) can be represented as (100cm).

I don’t have to treat it like a unit and I don’t. I’m simply saying that you can, if you want to.

By following a rule that says that all numbers used in an expression represent a quantity of the same unit. So instead of writing something like (3cm + 10cm = 13cm) you can simply write (3 + 10 = 13) because every number in the equation represents a number of units of the same kind (centimeters.)

That’s true. But how is that relevant?

en.wikipedia.org/wiki/Carry_(arithmetic

That’s a Wikipedia article (not a “Math for Kids” website) describing a very specific way to find the sum of two quantities. It’s definitely not the only way. You can add “6” and “7” together by placing six apples and seven oranges in front of yourself and then counting all of them. That’s not the same as the above.

Addition is a much more general concept, and saying that I’m talking about addition in general is not the same as saying that I’m talking about some specific algorithm for adding numbers. I did not the do the former, I did the latter.

Yes, and it’s wrong, and I explained why, even though it’s unnecessary. (One doesn’t have to prove more than it’s necessary.)

They don’t and I never said that.

Correct. We’re talking about infinite quantities, not the word “infinite” in general. The word “infinite” is not a quantity per se. Neither is “finite”.

This is one of the most pointless things you can say in a forum discussion.

You have to understand that this isn’t the subject of this thread.

Frustration isn’t something to be proud of.

I really just wanted to come in and stomp all over the twee debate and polite conversation being had. There’s a report button at the top of this post, if you click on it someone will come to the aid of the twit.

I’m going to get back to the .9…/1 part, I made a mental note in my head when I read the apple thing, that infinite apples would have infinite weight, this is really a physics argument. Each member being part of the whole set would have infinite weight as well, making it physically impossible to remove an apple in the first place.

It’s just a mental note, not completely thought through, but I thought you guys might find it interesting.

It’s not a physics argument. It does not matter what’s physically possible or impossible. This discussion is entirely about concepts.

An infinite number of apples can have any weight whatsoever. If each one of the infinitely many apples weighed exactly one infinitesimal kilos, then the apples as a whole would weigh exactly 1 kilo.

Not really. So there’s two philosophies to this as far as I can see.

Let’s say you count a trillion apples through, and you stop and count again. The first trillion apples would be outweighed by the rest of the set. Ones finite, ones infinite.

Now let’s think about this in terms of infinitely regressive sets - they’ll have the same weight.

Like I said! These are just notes!

So, thinking about infinitely regressive sets further…

If you only count the first 9 in 9/10ths… the rest of the infinite sequence combined should also add up to 9/10ths.

So there’s two ways you can look at it 9/10ths equals 9/10ths, or they are different 9/10ths.

If they are different 9/10ths, then adding them gives you 18/10ths, which I’m sure you’re not trying to argue!

So… when I consider the variables here, I definitely side on them being equal but not separate as additive properties.

I hope you and sil can understand that!

Yeah!

Oh, you guys are going to love this!

So, I was using my notes in the last two posts, and I realized a contradiction in convergence theory:

Get this!

So you have a number like 0.9… that converges to the number 1!

Here’s the deal. 0.09… is converging to 1 as well.
Meaning: 0.199… 0.009… is converging to 1 as well…

Meaning 0.01999…

What this means is that you end up with the “infinitesimal” before the 9’s necessarily have to start.

This means that as you count through the convergence, you either have infinitesimal 1 before the 9’s or you have the 9’s equaling 1.111…

Dammit! Ok, this is really important !!!

For 0.9… to equal 1, the solution is 3.1…!!!

Like I said before…

0.9… =1

That means that 0.01999… equals 0.2999…

0.2999… equals 3.1111…

I’m getting there! Let me work through this process!

If 1=0.9…

Then 0.009… = 0.01

Which means that 0.9… equals 1.1…

When you add those up,

You get 2.000…

That’s it!

That’s the disproof!

So what I’m trying to explain here, is that in the proof that 0.999… equals 1; ALL nines repeating always equal 1, which is why I say that the solution to 0.999 actually equals, not just 1, but 1.111… (unless you have an infinitesimal which is impossible (the one never gets expressed)

As I stated earlier, when you carry from the right to left, that makes 0.999… equal 2, with no infinitesimal to flip the 9’s, you’re still left with 1.999… which equals 2.

You want to get at the truth?

Work with me here.

I know I’m close.

Because an infinitesimal is impossible, you have to carry from left to right.

This causes all the 9’s to eventually be 1’s… which not equal to 1 but is equal to 1.1…

1.1… + .999… = 2

Some clarifications:

If you have an infinite line of people standing in front of you, and you remove the person standing at the end of the line (or at the beginning of the line, it’s the same thing), you’d have a shorter line of people standing in front of you. So even though the queue is a ray, and not a line segment, you can still talk about its length.

It does not. That’s because the symbol already has a meaning, one that has nothing to do with quantities. Even if, instead of using a known symbol, you used an unknown symbol to which you assigned no meaning, we’d still be talking about a symbol that does not represent a quantity.

The symbol (\infty) is by definition a quantity albeit not the kind of quantity we’re used to. By definition, (\infty) is a number greater than every real number which is why we consider expressions such as (\infty > 1) as being true. You can’t do something like that with your :male_sign: symbol. Indeed, the symbol has no defined relation to other numbers. Does (:male_sign: > 1)? We can’t know, the result is undefined.

The problem occurs with equations such as (\infty + 1 = \infty). True or false?

If what that equation means is “If you take some infinite quantity and add one to it, you’d get an infinite quantity as a result” then the equation is TRUE.

However, if what that equation means is “If you take some infinite quantity and add one to it, you’d get the same infinite quantity as a result”, then the equation is FALSE.

In the first case, the symbol of infinity represents ANY INFINITE QUANTITY IN GENERAL. In the second case, the symbol of infinity represents THE SAME INFINITE QUANTITY WHEREVER IT OCCURS.

The meaning of the symbol of infinity is what has to be well-defined in order to avoid making pseudo-proofs such as this one:

$$
s = 9 + \underline{0.\dot9}\
s \div 10 = \underline{0.\dot9}\
s - s \div 10 = 9 + 0.\dot9 - 0.\dot9 = 9\
s \times (1 - 1 \div 10) = 9\
s \times 0.9 = 9\
s = 9 \div 0.9\
s = 10\
$$

((9 + \underline{0.\dot9}) \div 10 \neq \underline{0.\dot9})

The two underlined numbers aren’t the same: the two infinite sums don’t have the same infinite number of non-zero terms (or in plain terms, they don’t have the same infinite number of 9’s.)

That’s why (0.\dot9 - 0.\dot9) in the third equation of the proof does not equal to (0).

The infinitesimal quantity has conveniently disappeared.

Well, geez, man, not sure how else to put it. “Fewer” implies finitude. It implies an actual quantity relative to a larger quantity. I shouldn’t need proof of this, that’s just the common definition. If you need proof, what you’re really asking is: why should I accept your definition when I have my customized one that fits with my theories on infinity. And to that I say: fine, we can go with either definition, but then you gotta help me understand your definition.

Let’s try this: imagine the scenario I described earlier, the one with two infinite parallel lines. For all intents and purposes, the same length. Now remove every odd point from one of the lines. Then move all remaining point into the spots left behind by the points you removed. According to you, the line with the points removed is now “shorter”. But since we moved all points into the spots left empty from the points we removed, the lines are perfectly identical. It’s as if we didn’t remove any points at all. We’re back to the initial state of the scenario. So here’s your chance to shine. Help me understand how the lines are different now. Help me understand what it means that the line we removed points from is now “shorter”.

You are, once again, dismissing counter-examples. Nothing wrong with following a string of logic to arrive at certain conclusions, but when someone shows you how counter-examples can be drawn in special case (like when the number is infinite), you can do two things: 1) dismiss it and just reiterate your original logic, or 2) consider the counter-example and rethink your original logic. You can then show how your original logic still holds and give an explanation for why, or you can concede that your original logic doesn’t actually hold in the special case of the counter-example. Seems to me like you’re choosing 1).

Unless we’re talking about Anderson’s magical fantasy world of shorter and longer infinities, this thread is about reality. The only way confusion would arise is if we insist on having contradictions between the concepts and the empirical evidence while still maintaining the concepts represent reality. If I say the concept of a flat world implies that you’d fall off the edge of the world if you walked far enough, and empirical evidence shows that you don’t, you’d only be confused if you insisted your flat-earth concept is still reality. The alternative is to accept that the concept is wrong. You can still say that the concept of a flat-earth implies that you’d fall off the edge if you walked far enough, but what good does holding onto that concept do if the empirical evidence shows that it’s wrong?

Ugh Ok, let’s try this. Infinity means no end. That means surpassing all numbers. As soon as you reach a particular number, you know you’re not at infinity because otherwise you could say you’ve reached the end of all numbers, and you know that just doesn’t make sense (right?). An infinite quantity just means beyond quantity. ← That’s why it’s not a quantity. Give me any quantity, any quantity at all, and I will show you it’s not infinity.

So then tell me, how many gwackometers is 1cm?

This should be good.

I am often amazed at what people need proof of.

Glad we got that cleared up.

So (\infty) stands for: an infinite number of Xs (organisms, train carts, points in line, whatever) where X is the unit, correct? Then I forbid you to use it in arithmetic. If (\infty) was the unit (as in 2(\infty) meaning 2 infinities), then I’d say run wild, have fun, but you’re not saying that. You’re saying you want to take the quantitative value of (\infty) and multiply it by 2, leaving whatever there is an infinity of as the unit, and to that I say: STOP IT! slaps hand

No, no, no, you’re just making the unit implicit. I mean, really get rid of it, as in you just have the number 13, not 13 centimeters, just 13. But this is a non-issue as I see above you don’t mean to get rid of units entirely but simply use whatever object there is an infinity of as the unit. Again, I forbid you!!! ominus voice echoing

You’re insisting that because symbols serve to represent something, we know what those are. But I’m saying that the whole point of variables (which are symbols) in algebra is to have a way of doing arithmetic with unknowns. You can know them, but you don’t have to. I was saying that if you want to use (\infty) as a variable, it has to stand for an unknown because the actual value of infinity is off limits.

I know I sound like an incomrehensible crazy person…

I’m working again on the 0.999… /= 1 argument, and if as Magnus states, silhouette is the “ecmandu whisperer”…

It’s a lot to ask silhouette, but can you help me disprove your proof that 0.999… does equal 1!!!

My argument is this:

The number 1 never occurs with the infinitesimal argument … thus, the 0.999… never falls like dominoes from right to left to create the whole number from the infinite sequence. Are we good so far??

So next, this means the only other option is to carry from left to right.

This means that you have to add 0.999… to 0.111…

The first time you do this you get 1.0999… and 1.0111…

The second time you do this, you get 2.10999…

See where I’m going with this sil???

Like I stated before, if you have no infinitesimal and the only other option is to carry from left to right, you have no equality for 1=0.999…

So, Silhouette! I’m asking you to “man up” here, and consider my argument is true.