I learned that 0,999... = 1. I believe it was in M381 that I learned to prove it. The proof is quite simple actually.

Let

x = 0,999..., multiply both sides with 10

10x = 9,999..., now subtract x from 10x

9x = 9, and we have our result

x = 1.

What I like about mathematics is that it is timeless, i.e. we can still read math books of hundreds of years old and still learn things from them. That's not an advisable strategy hfor any other science than mathematics. Of course, new branches of mathematics appear, new discoveries are made, but they don't invalidate the truths of the past.

Today however I found someone who actually is challenging some of the established truths in mathematics, like for example that 0,999... = 1. I don't think that he is a crackpot, although I have no doubt that the mathematical establishment, professors who are 'safe' by all means, will call him like that.

The man is arrogant though, he calls the proof above, 'juvenile' for example.

Who is he, what are his ideas and how did he disproof that 1 = 0,999? The links below will help you abshereing these questions.

- The New Calculus - The first rigorous formulation of calculus in history.

- Proof that 0.999 not equal 1.pdf

Update S383 and M303

3 weeks ago

is this from MIT?

ReplyDeletewhoever said tis is x-0.9999 close to being called an idiot (in math terms of course)

this runs along the lines of zeno's paradox

show me infinity and I'll show you where this is true

we say 0.999... "tends" to one and it could reach 1 if we had infinite number of tries but where is infinite?

your proof starts with the consequence

when we say pi=3.14... we don't mean that pi is equal to that number we mean that that number is symbolized by pi

we don't know that number we don't have that number