Prove 1=0.999...

Do not answer if you have seen this question before! Figure it out!

Question

Prove 1=0.999...

Do not answer if you have seen this question before! Figure it out!

anonymous · Answer

1/3 = 0.33333...
1 = 1/3 x 3
0.33333... x 3 = 0.99999....
1 = 0.9999....

turingtest · Answer

Very nice! The way I know to do it is

let x=0.999...
10x=9.9999
9x=9
x=1

pretty much equivalent. 

You're good, what do you study?

anonymous · Answer

I am still in high school

turingtest · Answer

damn, and you figured this out on your own?

turingtest · Answer

you didn't cheat by looking online did you?

anonymous · Answer

nope, this is kind of basic comparing to the math contests I do in school...

turingtest · Answer

Yeah I used to do those non-standard tests for this kind of thing in high school too. Still, very nice. I'm sure you'll be a kick-retricemathematician.

turingtest · Answer

kick-retrice
lol where did "retrice" come from?

turingtest · Answer

oh it won't let me type "A S S"

anonymous · Answer

lol I understand. Thank you

jamesj · Answer

@moneybird, are you in Australia?

anonymous · Answer

No, canada

jamesj · Answer

got it. I thought your koala might mean you were.

agreene · Answer

Pretty sure every proof I've seen for this is here: http://en.wikipedia.org/wiki/0.999...