Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: It is a very bad idea and nothing less than stupid to define 1/3
= 0.333...

Replies: 5   Last Post: Oct 4, 2017 3:15 PM

 Messages: [ Previous | Next ]
 Markus Klyver Posts: 730 Registered: 5/26/17
Re: It is a very bad idea and nothing less than stupid to define 1/3
= 0.333...

Posted: Oct 4, 2017 3:06 PM

Den tisdag 3 oktober 2017 kl. 22:04:52 UTC+2 skrev John Gabriel:
> On Tuesday, 3 October 2017 15:40:54 UTC-4, burs...@gmail.com wrote:
> > Nope, doesn't make any sense at all. Just plain
> > crazy. Why would you write a formula for a partial
> > sum as a number:
> >
> > If ... means n-th place, then this here:
> >
> > 0.999...
> >
> > Would mean:
> >
> > 1-10^(-n)
> >
> > So it would not be a number, but an expression with
> > a varying place holder n. Making this exxpression
> > here also dependent on n:
> >
> > 0.999... = 1
> >
> > But fact is that the following expression:
> >
> > 0.999...
> >
> > Has the meaning:
> >
> > lim n->oo (1-10^(-n))

>
> No. 0.999... = \sum_{k=1}^{\infty} 9/(10^k)
>

> >
> lim_{n \to \infty} \sum_{k=1}^{n} 9/(10^k) has the value:
> >
> > 1
> >
> > Am Dienstag, 3. Oktober 2017 21:15:40 UTC+2 schrieb netzweltler:

> > > The meaning of "..." is absolutely clear in this context and we both know that there is a nth decimal place for each n ? N in 0.999...

\sum_{k=1}^{\infty} 9/(10^k) is defined as lim_{n \to \infty} \sum_{k=1}^{n} 9/(10^k). Hence, 0.999... = 1.

Date Subject Author
10/3/17 bursejan@gmail.com
10/3/17 bursejan@gmail.com
10/4/17 7777777
10/4/17 Markus Klyver
10/4/17 genmailus@gmail.com