Scotty2Cues
Established member
- Messages
- 737
- Likes
- 33
No, the division at the end is fine. The flaw lies at the beginning of the proof in assuming that a = b.
no because youre dividing by zero as a = b
No, the division at the end is fine. The flaw lies at the beginning of the proof in assuming that a = b.
no because youre dividing by zero as a = b
Yes, I understand, but we are working sequentially from up to down in solving the equation. The mathematical steps are correct, but the assumption is not.
there is nothing wrong with a = b and everything is tickety boo (= fine/happy/correct) up to
2(a^2 - ab) = a^2 - ab. (*)
You cant then divide by a^2-ab because a = b and so (a^2-ab) = 0
The correct way to proceed is to rearrange (*) to get
2(a^2-ab) - a^2-ab = 0 and factorising this gives (2-1)(a^2-ab) = 0
and this implies either 2-1 = 0 (which it doesnt) or a^2-ab = 0 which it does as a = b so no contradiction
This one always causes controversy
0.999~ = 1
thats easy to prove, its GCSE maths
Yes, what you say is right. But remember, your argument depends critically on substituting a for b in equation (*). We could have done that much earlier in the proof but chose to proceed with the original variables as they are, throughout the proof.
The division is correct - dividing both sides of an equation with the same number/variable is okay to do in this.
I learned this proof in my first year of undergrad. As a challenge, our prof had asked us to determine what was wrong with the proof, and those who got the answer right would a bonus mark. After all submissions, our professor had revealed to us that the fallacy of the proof lied not in the math, but only in the assumption that a = b.
I didn't say it was hard, I said it always causes controversy. Search it on google.
I didn't say it was hard, I said it always causes controversy. Search it on google.
whts the controversy? got a link?
This one always causes controversy
0.999~ = 1
It seems to me now that mathematics is capable of an artistic excellence as great as that of any music, perhaps greater; not because the pleasure it gives (although very pure) is comparable, either in intensity or in the number of people who feel it, to that of music, but because it gives in absolute perfection that combination, characteristic of great art, of godlike freedom, with the sense of inevitable destiny; because, in fact, it constructs an ideal world where everything is perfect but true
Bertrand Russell (1872-1970), Autobiography, George Allen and Unwin Ltd, 1967, v1, p158
And let's not forget another great mathematician, Leonardo Da Vinci, and his centuries old (ahead of his time) quote on trading and mathematics;