is it a valid proof

[Guest]

My teacher give me a challenge to proof that 0,99999999999999999999.............=1
Then he give the answer :

assume that 0,999999999.....................=n
9,99999999999..................=10 n
9+0,999999999..................=10 n
9+n = 10 n
9 = 9 n
so,n = 1

is it RIGHT ???

 

[stapel]

One might quibble about the multiplication process, but what you have posted is generally accepted as an informal proof.

Do you accept that 1/3 equals 0.333...? If so, what is 1/3 + 1/3 + 1/3?

Eliz.