General / Off-Topic Does 0.999999999... =1?

Q. What do you get if you put 20 software developers in a room and shut the door?

A. A discussion like this one. :p


Mathematics is capable of embracing concepts that may or may not have any correspondence in the real world. From a Mathematician's perspective 0.9 recurring and 1.0 recurring are both mathematically equivalent in value to 1.

0.99999999... + 0.99999999... = 1.99999999... :)


*Sits back and waits for counterexamples...*
A Counter-example
 
Two numbers are the same if there is no real number that can come between them. There is no real number that fits between 0.9999... and 1. Ergo, they are the same number.

But I prefer the other version given above:
1/3 = 0.3333...
3* 1/3 = 0.9999...
1 = 0.9999...
 
The 9's can go on infinitely, out of the monitor to my neighbor's house across the street to our neighbor Andromeda galaxy and so on, and yet, does this make 1.0? It's ridiculously confusing.

https://www.youtube.com/watch?v=x-fUDqXlmHM

Should help (or maybe not) as there are 3 algebraic sums you can do with the same logic as yours:

1) 0.99... = 1
2) ...999 = -1
3) ...999.999... = 0

Watch to blow your mind :D
 
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Funny, I have been unsure what to think of this question until I realized the proof with fractions.

0.3333... = 1/3.
3x 0.3333... = 0.9999...
3x 1/3 = 3/3 = 1
Therefore, 0.9999... = 1
QED :)
 
https://www.youtube.com/watch?v=x-fUDqXlmHM

Should help (or maybe not) as there are 3 algebraic sums you can do with the same logic as yours:

1) 0.99... = 1
2) ...999 = -1
3) ...999.999... = 0

Watch to blow your mind :D

Yup. Pretty much what I said in my previous post. Infinity in Mathematics turns out to be a somewhat flexible notion. :)

Just to throw a little something else into the pot.

1 is, amongst other things, a natural number.
0.99999... is real number

Between any distinct pair of natural numbers there is an infinite number of real numbers. Ok so far?

There is an infinite number of natural numbers. Which means that the number of reals is infinity^2 (sort of...).

In plain English, there are different levels of infinity.

Disclaimer: I've messed about with the theory a bit - it's not quite as simple as I've made it look...

Further reading
 
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Indeed - I subscribe to numberphile on YouTube and there are a couple of vids talking about infinity and the different kinds.

I enjoy melting my mind :)


(Yes, I followed you - aware of the different kinds of infinities when talking about number sets : beyond my level of school education but fascinating to learn all the same)
 
The margin of error when dividing into thirds is easily explained as the bit that comes away on the knife that nobody can lick off.

Problem solved. Back to work!
 
The margin of error when dividing into thirds is easily explained as the bit that comes away on the knife that nobody can lick off.

Problem solved. Back to work!

There is no "margin of error". A third is precisely a third. It is just a random happenstance that we use a decimal system which cannot display it in decimal notation without the use of periods. If we were using one of the other numeric systems that have indeed been used by humans in the past, like the base-12 system, 1/3 could easily be represented with decimals and no period at all.
 
There is no "margin of error". A third is precisely a third. It is just a random happenstance that we use a decimal system which cannot display it in decimal notation without the use of periods. If we were using one of the other numeric systems that have indeed been used by humans in the past, like the base-12 system, 1/3 could easily be represented with decimals and no period at all.


Pssst...


















I've met this one before. I'm pretty sure she was joking...
 
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