mathematical theory

Rebelius · 12 May 2007 at 15:58

aleph-null and aleph-one aren't really different sizes of infinity. Infinity is just infinity, sometimes defined as the extreme limit of the extended real number line. It's not a number, it's just infinity. The aleph numbers are measures of the size of infinite sets.

to the above: it's not a theory - it's a fact, 0.9r is just a different way of writing 1.

manoz · 12 May 2007 at 15:58

markyp23 said:
Also 0.999... = 1

x = 0.999...
10x = 0.999999...
10x = 9.999...
10x - x = 9.0000....
9x = 9
x = 1

Love that theory.

Except you borked it on the 2nd line

Calder · 12 May 2007 at 16:04

manoz said:
Except you borked it on the 2nd line

never mind me, brain isn't working.

Rebelius · 12 May 2007 at 16:08

but it won't because there's INFINITELY many 9s - there is no end to them.

it's like saying 0.9r = 1-0.000...1 but the 1 never comes.

edit: damn, should've quoted

Psyk · 12 May 2007 at 16:12

Rebelius said:
but it won't because there's INFINITELY many 9s - there is no end to them.

it's like saying 0.9r = 1-0.000...1 but the 1 never comes.

edit: damn, should've quoted

But you are taking an infinite amount of 9s from another infinite amount of 9s. So you are left with 0, or in this case 9 as there's a 9 just before the decimal point.

Calder · 12 May 2007 at 16:13

Rebelius said:
edit: damn, should've quoted

I'm glad you didn't.

Rebelius · 12 May 2007 at 16:13

I was replying to calder saying there would eventually be an 8 on the end.

NickK · 12 May 2007 at 16:13

FrostedNipple said:
right, im having an argument with a m8, i am saying that if you divide a number by 0 then you get infinity, he is saying you cant divide by 0, and backing up his ideas with a pizza theory (ie he cuts it up)

im basing my knowledge on my physics teacher, i think i heard him say something about it!

who is right?

FN

Actually you can cut a pizza up into zero sized slices hence you end up with an infinite number of slices.
He's just proved your point

Some interesting maths going To Infinity and Beyond!

Calder · 12 May 2007 at 16:14

Rebelius said:
I was replying to calder saying there would eventually be an 8 on the end.

Who said that, wasn't me, must have been someone else. :eek:

Back to the maths revision I think.

Beansprout · 12 May 2007 at 16:14

markyp23 said:
Also 0.999... = 1

x = 0.999...
10x = 0.999999...
10x = 9.999...
10x - x = 9.0000....
9x = 9
x = 1

Love that theory.

OH GOD DONT START THAT AGAIN :eek:

Calder · 12 May 2007 at 16:15

NickK said:
Actually you can cut a pizza up into zero sized slices.

No you can't. What's a "zero sized slice"? The air next to the pizza? In which case you aren't cutting the pizza.

Rebelius · 12 May 2007 at 16:15

NickK said:
Actually you can cut a pizza up into zero sized slices hence you end up with an infinite number of slices.
He's just proved your point

erm... no.

Duff-Man · 12 May 2007 at 17:02

Infinity can only be described mathematically in terms of a limit.

As for dividing by zero - you don't get "inifinity" - the division of a number by zero is an undefined operation. I'm afraid your friend is correct.

The various shoddy "proofs" you see floating about which prove 1 = 2 and other absurdities take advantage of the fact that by dividing by zero you can produce anything you want (hence the undefined nature of the operation).

I can't be bothered explaining further, but trust me - I did maths at Cambridge

oh, and 0.9999... = 1, whether you guys want to accept it or not

Calder · 12 May 2007 at 17:03

Duff-Man said:
I can't be bothered explaining further, but trust me - I did maths at Cambridge

Can I touch your e-peen?

Duff-Man · 12 May 2007 at 17:04

Calder said:
Can I touch your e-peen?

If you can get your hands around it, sure

xsnv · 12 May 2007 at 18:58

Duff-Man said:
Infinity can only be described mathematically in terms of a limit.

Not true. Infinite sets exist and are a cornerstone of set thoery.

iraiguana · 12 May 2007 at 19:23

You will never get size zero sized objects for the same principle you cant have an infinite amount of them. In theory yes it would have to work that way as you tend to zero you are capable of having more of it and thus tend to infinity. But its impossible to reach these states as it would then be defined and you cant.

Its like quantum mechanics, you cant 'know' a finite thing but you can have information about it. (applied chemical quantum mechanics people!)

Amleto · 12 May 2007 at 19:31

Gentlemen, the question of utmost importance you have to ask yourself is this:

If you cut a single sandwich in half, do you have one sandwich, or two sandwiches?

iraiguana · 12 May 2007 at 19:52

you would have two halves of a sandwich. by definition of there being one original sandwich. split in half

daz · 12 May 2007 at 19:53

iraiguana said:
Its like quantum mechanics, you cant 'know' a finite thing but you can have information about it. (applied chemical quantum mechanics people!)

Can you explain what you mean by this. I assume you just mean that a pair of conjugate observables can't be measured precisely...? Not sure what this has to do with dividing by zero? :confused: