More on 0.999~ vs 1: Comparing Numbers

  • Context: Undergrad 
  • Thread starter Thread starter BSMSMSTMSPHD
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the mathematical relationship between the numbers 0.999... and 1, exploring concepts of limits, representations of numbers, and the implications of infinite sequences. Participants engage in a debate over whether these two representations can be considered equal, touching on theoretical and conceptual aspects of mathematics.

Discussion Character

  • Debate/contested
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • Some participants argue that if two real numbers are different, there should be another number between them, suggesting that since no number exists between 0.999... and 1, they must be the same.
  • Others question the equivalence of 1/3 and 0.333..., suggesting that the infinite nature of the decimal representation complicates the comparison.
  • A participant asserts that the definition of a number's representation does not depend on the infinite digits but rather on the limit of the sequence of its decimal representation.
  • Some participants express confusion over the implications of limits and continuity, particularly regarding the function f(x) = (x^2 - x)/(x - 1) and its behavior at x = 1.
  • One participant introduces a metaphor involving a runner on a track to illustrate the concept of incompleteness in the representation of 0.999... compared to 1.
  • Another participant emphasizes the importance of defining what is meant by "complete" when discussing numbers, indicating a need for clarity in the terms used in the discussion.
  • Several participants discuss the mathematical definition of limits and how they relate to the concept of infinity, arguing that 0.999... approaches 1 as a limit.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus reached on whether 0.999... is equal to 1. There are competing perspectives on the nature of numbers, limits, and the implications of infinite sequences.

Contextual Notes

Some participants highlight the confusion surrounding the concept of limits and the representation of numbers, indicating that assumptions about completeness and continuity may vary among contributors.

  • #61
d_leet said:
It definitely does not show that 0.9999=1, .9999 = 9999/10000 which is not equal to one, but if we take the notation that .999... represents the infinite geometric series with .9 as the first term and 1/10 as the common ratio then this is equal to one .999... = 1.

I wanted to say 0.9999...
I always talked about 0.9999... but i forgot the ... because that's not the notation I learned.
I learned that if you want to write...let's say 0.6767 repeating you write
0.(67) in parenthesys like that. But you all use the ... instead so I tried to use yours but at times I forgot it.

0.9999 is a banality to convert...also an irrelevance.
However 0.(9) using the method I did with the long number as example would look like this:

(the whole number - the non-repeating number)/as many 9s as different repeating decimals followed by as many zeroes as the decimals not repeating.

So...

(09-0)/9 is just 9/9 or 1.
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 46 ·
2
Replies
46
Views
8K
  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K