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Submission Info

Posted by: verificationist

Posting time: 3.3 years ago on

Last edit time: never edited.

Archived on: 2/12/2017 1:51:00 AM

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Views: **426**

Score

SCP: **24**

**24** upvotes, **0** downvotes (**100%** upvoted it)

- system [O]

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## Sort: Top

[–] marius_siuram 0 points 1 points 1 points (+1|-0) ago

I'm a mathematician, and that video was inaccurate and not very educational, IMHO.

Fortunately, the video didn't say "10

proofswhy...", otherwise I would have had to deintoxicate myself.Again, I am not in /v/askscience or /v/science, so... ok, I should not be an a** about that xD

[–] verificationist [S] 0 points 0 points 0 points (+0|-0) ago

What is inaccurate about the video?

[–] InsaneMonkey 0 points 0 points 0 points (+0|-0) ago

How about the fact that a number that is not 1 can not be 1.

That would be like saying Pi is 3.1

[–] marius_siuram 0 points 0 points 0 points (+0|-0) ago (edited ago)

Disclaimer: at first, I thought that "nine repeating" was a layman term to refer to those types of decimal numbers. (My native language uses a more specific term, and I was expecting a more explicit term than

repeating, which confused me. So I thought that the video was abusing this layman term.One thing that I didn't like was the "because it works" as a reason.

Also, the video does not start with a clear definition of the repeating decimal. The narrator has a lot of mathematics knowledge, but either oversimplifies things or jumps to conclusions too quickly for being a "general public" video.

I (personally) think that using repeating decimals is a bad approach to using fractions (all repeating decimals can be expressed as a fraction, and all fractions can be expressed either with finite decimals or with a repeating decimal). But the video does not justify the origin/existence/meaning of a repeating number. Which should be addressed before discussing the matter.

Again: Maybe I am overthinking it and this is not subverse for it. Sorry about that!

Edit: I forgot: the Zeno paradox was badly handled, IMHO. Confusing at least.

[–] generalwarning 0 points 1 points 1 points (+1|-0) ago

Round UP!

[–] spexdi 0 points 0 points 0 points (+0|-0) ago

Or....don't round where you can... 0.333333333(infinite) is the closest we can calculate numerically to 1/3, and in space, where someetimes inches in precision matters, the more decimal places you can calculate for, the more accurate your calculations

Example post of somebody asking the question I am describing

[–] thebestjohn 0 points 1 points 1 points (+1|-0) ago (edited ago)

https://www.youtube.com/watch?v=wsOXvQn3JuE and now I'm confused as to what the fool was the first or the second?

[–] blueberryapple 0 points 1 points 1 points (+1|-0) ago

Look at the videos date =D

[–] foh_tang 0 points 1 points 1 points (+1|-0) ago

I thought my brain hurt after watching the first one, but I was wrong

[–] verificationist [S] 0 points 0 points 0 points (+0|-0) ago

The one that I posted is the real one. The fake one (intentionally) makes a lot of mistakes. For example, it is true that x was 1 all along. But that doesn't mean that you're presupposing that x=1. x works simply as a pretend name for whatever 0.999... denotes, so when you say at the beginning that x=0.999... you're basically just saying that 0.999... is identical to itself. This is obviously true for any number whatsover, so you're not assuming anything about 0.999.. that isn't true of any other number. Every other step of the proof proceeds according to universal algebra laws. Hence the proof is valid. (If your not convinced, check the following: you can carry out the whole proof by writing 0.999...=0.999... at the beginning and repeating the whole proof by writing 0.999... instead of x. No need to use x at all.) Or, if you want a more pedantic explanation, what the proof demonstrates is this: For every number x, if x=0.999..., then x=1. So in particular, we have that if 0.999...=0.999..., then 0.999...=1. But obviously 0.999...=0.999... so 0.999...=1.

[–] spexdi 0 points 0 points 0 points (+0|-0) ago (edited ago)

I hurt my brain trying to read all that and i still have no clue what you are talking about.

@ 2:12 in you example video...

If x=.9999...

But lets use their calculation as they try to...

Crap, didnt get very far... ok...how about this...

9 = 9x? what? how?....they subtract 1x in the middle of the equation!....going back to original equation...

What you do to one side of the equation, you must do to the other side to balance it out, You cannot subtract x from one side without doing the same to the other side. I'm no expert, but I hope you see the flaw in your submission, and how the comment we are replying to is correct...

[–] OptimusLime 0 points 0 points 0 points (+0|-0) ago

The vocal fry killed me, didnt make it through the whole video unfortunately.

[–] InsaneMonkey 0 points 0 points 0 points (+0|-0) ago

No, it doesnt. None of what she said make any sense at all. a number that is not 1 is still not 1 no matter what bullshit tricks you pull to try and make out it is. This is as lame as the old "There is no extra dollar" puzzle.

[–] blueberryapple 0 points 0 points 0 points (+0|-0) ago (edited ago)

By far, I think the informal proof with the geometric series in the video is the strongest.

a/(1-r) =

.9/(1-.1) =

.9/.9 =

1

edit: I'm a retard.

[–] totes-mah-voats 0 points 0 points 0 points (+0|-0) ago (edited ago)

I'm not a mathematician, but this strikes me as a logical fallacy based on a flawed philosophy. I like mine better.

All numbers are concepts. An integer, like 1, is the concept of something existing as a perfect, self contained value. Infinity is also a concept, and is by definition a value without limit. Both represent different kinds of values.

Think of geometry:

A single point is a one dimensional space -- it is a single value, like 1.

A ray, on the other hand, may start at a single point, but stretches into infinity, making it two dimensional -- it is a collection of both infinitesimally and infinitely expanding of values, like .9 repeating.

Points can make up rays, lines, or segments (remember, the space between any two points is infinite, so infinity applies to segments too), but the inverse is impossible.

.9 repeating perpetually approaches 1, but you can't say it equals 1, because they are different concepts altogether. This is apples to oranges, though you could say that .9 repeating is effectively equal to 1, even if though it really can't be.

[–] Bodhidharma 0 points 0 points 0 points (+0|-0) ago

Smart Clowns! The inventor of Graham's number was also a clown. evidence