Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#76 Re: Help Me ! » Please solve my question » 2007-07-10 09:16:34

Hi ricky.
No I mean


and you can't chose the functions - should prove it for all functions f, g : [0,2c]->[0,2c]

#77 Re: Help Me ! » Please solve my question » 2007-07-10 09:09:48

I think the question is:
Given two real numbers

and two functions
then show there is a numbers
such that

I think you should give more restrictions for f,g, because now it's only a mapping of [0,2c] to [0,2c]...
But I can't figure out an example right now.
I'll post later.
EDITED

#78 Re: This is Cool » 0.9999....(recurring) = 1? » 2007-03-13 09:36:14

To : Anthony
Note: very funny way of posting smile
It could be better if the posts were true. tongue

#81 Re: Help Me ! » Unproved theorems » 2007-03-12 22:39:15

Zhylliolom wrote:

The Millennium Prize Problems are the most popular unsolved problems in mathematics which have a prize:

http://en.wikipedia.org/wiki/Millenium_problems

And the most advanced

#82 Re: Help Me ! » Proof » 2007-03-12 22:08:35

I haven't learned about linear dependence, kernel, or morphism

Better learn it first.
Linear dependency for vectors basically means, that every has a little "different dimension" form theothers.
Formally, a system {A,B,...,Z} is lineary independent only and only if the equation
aA+bB+cC+...+zZ=0 doesn't have solutions, different from {0,0,...,0} for real a,b,...,z.
For example, if two vectors A,B are collinear, then A=mB, m e R (=/= 0), so
1.A-m.B=0, 1,m =/=0 ==> A and B are dependant.

#83 Re: Help Me ! » Natural Number » 2007-03-12 12:03:44

Ricky wrote:
Sekky wrote:

Use the natural numbers as the group you're operating on, and only use operations that will form a group under the naturals

(Silly question)

Is always a natural, even though division won't form a group under the naturals.  So you are missing out many of functions by doing as you advised.

There's someting very more general than the binomials:

is integer, where
are integers.
(that follows from

and

)

#84 Re: Help Me ! » Natural Number » 2007-03-12 11:57:05

luca-deltodesco wrote:

i thought

denoted rounding the number, [0.3] = 0, [0.8] = 1, [0.5] = 1 etc.

and then:

denotes the floor of the number, 0.3 -> 0, 0.8 -> 0

and then:

denotes the ceiling of the number, 0.3 -> 1, 0.8 -> 1

luca and jane, you're not absolutely right. The notation [.] is an old floor-notation. Today we use \lfloor ect. , but if you look at some notebooks from the 80's, for example, you'll see there floor is [.] . Now [.] is used for another notation.
It's something like the natural number - definition, different in different countries.

#86 Re: Help Me ! » trig proofing. very smart person needed » 2007-02-03 22:06:50

you're searching for:


You can use:

and:
to get formula only with sin and cos

#87 Re: Help Me ! » series2 » 2007-02-03 21:53:46

2. John, you're right.
for |x|<=1 the second coverages, and it's:

#88 Re: This is Cool » My Great Theory » 2007-02-03 12:40:12

No, no!
Maths is not "invented" by a human.
It's somthing abstract, you can't feel it, touch it, but still "it's there"! tongue
The signs and the equations are just one picture of the math, which the human created.
Mathematics is some kind of invariant. It's unchanged over the universe, it's abstract, and doesn't depend, for example of the length of plank (as in phisycs). It's a mental ocean of knowledges.

But I've ever asked some kind of weird questions : how far can math go? which are the boundaries of the abstraction? Can we do everything with it?
And the other question - what is the structure of mathematics? So far we're proving beautiful theorems in different fields of maths, but no one (with little exeptions) has fully understood a field - that is, to form some kind of intuition to answer some questions whitout proving them.
And another - what is the mathematics made from? And who controls it?
There are weird mathematical paradoxes too, which ;ie in the foundamentals. For example the Goedel's incompleteness theorem - that we can't have math that proves or disproves everything - that maths has limits.
Another interesting contemporary structures are so strange, that nothing can be proven about them at all.
I'll give you an exampe: the infinite random sequence.
Many paradoxes are connected with it. It's proven, that the mantissas of almost every real numbers are such random sequences. But in fact, such sequence is unconstructible! There's no example of truly random infinite sequence!
Another example, which is more fascinating, is the halting probability : the probability arbitary computer program to halt.
It is shown that this probability exist, and is between 0 and 1, but is algoritmically unpreictible - that is, we'll can never know what is, for example, its 100th digit!

Is the mathematics inconsistent? Nobody (with little exeptions) knows. And we can't be sure until we find a crack in it.
But after 30000 years evolution, we've still not understood the "mattery" of the mathematics - the language of the universe we live in.

#90 Re: This is Cool » INFINITE 0.9 <> 1 PROOF By,Anthony.R.Brown,15/01/07. » 2007-02-03 11:59:22

smile
Again the old story! smile
Anthony, just try to beleive all the people telling you that
0.999... = 1!

#91 This is Cool » Simple, but... » 2007-02-03 11:50:33

krassi_holmz
Replies: 6

There are 3 flies on a sqare table with side 1.
You have circle flapper with diameter 1.
Can you be sure that you can kill at least 2 flies with 1 hit? (if you are very presice, and assuming the flies are slightingly small)
And Why?
big_smile

#92 Re: Help Me ! » need help (ALGEBRAIC EXPRESSION) » 2007-01-21 00:21:00

I told you - the question is wrong. There doesn't exist any x satisfiyng the conditions.

#93 Re: Help Me ! » Strange Prime number pattern » 2007-01-04 00:53:08

I don't know.
But here's some results:
There's a theorem, stating that for every number k, there exists infinity couples of consecutive prime numbers, such that the gap between them is greater or equal to k. Graphically that means, that when we have enough prime numbers, this graphic will cover some square, no matter what the square side is. More basically, this structure grows.
Not so helpful, but it's proven to be true.

#94 Re: Help Me ! » fractions » 2007-01-03 13:08:01

Toast wrote:

Quite interesting.

I don't know if this will be any help to you, but you're just multiplying the top and bottom by 11, 111, 1111, 11111 etc.

Excellent! Good obsrvation, toast!
The answer is simple: just:
477...773 = 11..11*43 (k 7's and k+1 ones)
377...774 = 11..11*34 (k 7's and k+1 ones)
smile

But it's interesting.

#95 Re: Help Me ! » Strange Prime number pattern » 2007-01-03 12:55:46

BluemanSteele wrote:

Great to hear Ricky!

I'm going to describe it similar to text processing. I'm sure there is a much more efficient way to do it, but this will be easier to describe. My algorithms are less than text-book quality so I'll leave them out.  This is a bit of a repeat from above but I'll post it that way for clarity.

1. Create (or read from) a list of prime numbers starting at 3

      (3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61...)


2. Make a list of the differences between on number and the next.

      3 -> 5 = 2
      5 -> 7 = 2 ...

      (2, 2, 4, 2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6, 2, 6 ...)

3. Take the first two numbers in the list (n1 and n2) and plot them as coordinates.

4. Do the same for either a. (n3 and n4) or b. (n2 and n3), I've found both produce interesting results.

   That is take... 
      (2, 2, 4, 2, 4, 2, 4, 6, 2, 6, 4, 2)

   And plot points
      (2,2) (4,2) (4,2) (4,6) (2,6) (4,2)

    OR. plot to points
      (2,2) (2,4) (4,2) (2,4) (4,2) (2,4) (4,6) (6,2) (2,6) (6,4) (4,2)

5. Since all numbers are even,optionally divide all numbers by two to collapse the resulting shape of negative empty areas.

Let me know if you have any questions if I have not been clear.  I'd post my Python but eek do I have to show the world what a horrible coder I am???  :-)

I made the same.
Only for optimisation: there are many "fast" tests for finding the next prime. I recommend you download some library for computing primes, instead of computing them using Erastritenes' sieve of brute force.
That will save much time for big primes.

#96 Re: Help Me ! » Strange Prime number pattern » 2007-01-03 12:48:03

Here are two plots, made them with mathematica.
The first is for all numbers to the 100000th prime number (not 100000)!
The second - to 1000000th prime number:

#97 Re: Help Me ! » Strange Prime number pattern » 2007-01-03 12:22:35

Are there any interested C programmers who could take pseudo code and optimize it?

And I cna use Mathematica for some big primes.

#98 Re: Help Me ! » Strange Prime number pattern » 2007-01-03 04:32:35

Intersting.
There's a conjecture, that for every even n, there exists infinitely many prime couples (p,q), such that p-q=n.
Intersting pattern.
Does your avatar has some connection with this?
I like it very much.

You can upload images, using "upload image", when you're posting and using  the

[img]

tag.
Something like:

[url]http://the_place_where_your_image_is[/url]

You can also read the forum features.

#99 Re: Help Me ! » graphing » 2007-01-03 04:21:35

And, of course, you can use the Mathsisfun Function Grapher:
http://www.mathsisfun.com/graph/function-grapher.php
smile

Board footer

Powered by FluxBB