Let's discuss Mathematics

@Ayatollah, some remarks:

1. If you want, you can get rid of the subjectivness by not explicitly giving values to each number, but instead saying that s:N->[0,1] is speciality-function, and perhaps giving some more conditions, like s(0)=s(1)=1 etc. If you want this proof to work, you must of course add some rule to ensure it.

2. To give numbers you can also use some nonsubjective method. I think the length of it's description is one that is pretty close to the intuitive one: "The multiplicative unit" has speciality of 1, the least prime has 1/2 /the words "least" and "prime"), and "the least odd prime" has 1/3 (the words "least", "odd" and "prime"). This is relative to the properties we allow on this list of course.

3. Even in fuzzy sets this proof can work, if you think that "not special" means speciality of 0. This would prove that all the numbers have speciality bigger than zero, and that's of course possible. All numbers are special, some of them are just more special than the others.

The additional rule we had to have for function s of remark 1, would then be that s(n)>0 for the least number for which s(n)=0. This is of course the same thing as saying s(n)>0 for all n in N. And this is of course because we are taking off the fuzzines by reducing non-speciality to something that can have ionly two values, 0 and >0.

4. I just understood that I've been trying to figure ot what we must assume of specialness to make the proof work, and you have been thinking is the proof valid. Thus all the comments above may seem to be tangential to the problem.

@Harbinger, what pre-algebra means? If you don't know much about maths, rushing into university/college stuff isn't probably very good idea. You can instead learn about ancient geometry for example. It doesn't require much knowledge, but shows pretty clearly what maths is about. It rarely is covered in universities, so you won't be doing the same thing twice.

You'll have to do exercises also. If you don't like it, it's better to concentrate on something else.
 
No it isn't if there is no least number for which s(n)=0.

It's quite a common error to assume that min or max exists, or that inf and sup are in a real number set.
 
Well, if you include "would then be that s(n)>0 for the least number for which s(n)=0", you say that there's no n with s(n)=0, since if there was such a n, there would be a least number too, and that would be a contradiction. So really, you're defining special in such a way that there can't be a non-special number, and then you prove there can't be a non-special number.

(note: I don't know if this is what you were trying to say in post #206, I couldn't really follow your line of thoughts from halfway through 3)
 
That is what I tried to say, that the claim becomes trivial. I probably should have said it explicitly though.

I have a bad tendency to think that the person who reads thinks the same things that I do while writing, and as a consequence I sometimes don't understand my own texts after forgetting what I was thinking :D
 
Another way to define s would include
if n is the least number that would otherwise have s(n)=<10^-n --> s(n) := 10^-n.
This way, 0 would be a limit point of s(n)
 
Cauchy would not be pleased dutchfire.

How about given any epsilon > 0 we can find an N such that for any n > N, s(n) < epsilon

;)
 
Well, that clearly doesn't work, since, between all these non-special numbers, there'll always be some special ones (primes, powers of 10, etc.) That's why I was talking about a limit point, and not a limit.
 
What does BC stand for?
 
Solve in N* (or in Paradigm's case, in N)
a3 = b3 + c3 + 12 a
a2 = 5(b+c)

Two equations, three variables :)
 
I haven't got Excel :(

Shame it isn't in Z\Z- bcos a=b=c=0 is a solution ;)
 
Bivariate calculus calculus? Maybe not ;)
 
125 = 1 + 64 + 60
25 = 5(1+4)

Yep that's good, symmetry.

EDIT: Proof there's no more?

EDIT2: Whoops, 4 != 5
 
EDIT: Proof there's no more?

(I) a^3 = b^3 + c^3 + 12a
(II) a^2 = 5*(b+c)

a,b and c are >=1

that means that according to (I) a > b

Let us assume that b >= c (the argument for c >= b is the same)
For (b+c) = 20, a = 10, but b >= 10, so a > b isn't true.

Because da/db < 1, a < b for all a > 10. That means there cannot be any solutions for a >= 10.

As trying out any combination with b,c < a < 10 (okay...I didn't do that, I asked Mathematica :mischief:) doesn't yield any other solution, but those two, there are no more than 2 solutions.
 
:thumbsup: Uppi has got it.

How to get there: a^2 is divisible by 5 -> a is divisible by 5 en b+c is divisble by 5.
From the first equation: a > b and a > c so 2a > b+c so a^2 = 5(b+c) < 10a so a<10, so a = 5 and b+c=5. Now there's 5 possible solutions, trying them gives 2 correct solutions.
 
A factory makes tables of 40 x 40 cm^2, the top is made out of 4 identical tiles of 20 x 20 cm^2. These tiles are asymmetrical (imagine they contain an arrow pointing in a direction). By rotating these tiles, different tables can be made. For example:

up up
down down

However, some of these possibilities are identical, for example, the table

up up
down down

is identical to the table

left right
left right

by rotating it 90 degrees. How many unique tables can this company make?
 
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