## Search found 209 matches

- Wed Aug 15, 2007 10:56 pm UTC
- Forum: Mathematics
- Topic: Help with this theorem - accumulation pts and cpt sets
- Replies:
**11** - Views:
**2573**

### Help with this theorem - accumulation pts and cpt sets

Just learning about compactness so please bear with me THEOREM Let S* denote the accumulation points of S. Assume: 1) K is compact 2) S is a subset of K 3) S is infinite Then: S* intersect K is not empty I understand the proof of this, but what I don't understand is why bother with S* intersect K? A...

- Wed Aug 15, 2007 10:39 pm UTC
- Forum: Science
- Topic: Synchronized wheels
- Replies:
**13** - Views:
**3125**

I studied rolling wheels on my walk back from school and I'm now also completely certain that the synchronizing effect is caused by the cleanliness and uniformity of the wheels that produce said effect. EDIT for comprehension: Uniformity meaning one wheel doesn't have one broken plastic hub cap spok...

- Tue Aug 14, 2007 9:16 pm UTC
- Forum: Science
- Topic: Synchronized wheels
- Replies:
**13** - Views:
**3125**

I don't think it's confirmation bias so much as it might be an optical illusion. I'm not recognizing any patterns here, just every once in a while the two wheels rolling to a stop catch my eye. This would be almost a classic example of confirmation bias; the only time you notice an experiment is wh...

- Tue Aug 14, 2007 8:54 pm UTC
- Forum: Science
- Topic: Synchronized wheels
- Replies:
**13** - Views:
**3125**

I don't think it's confirmation bias so much as it might be an optical illusion. I'm not recognizing any patterns here, just every once in a while the two wheels rolling to a stop catch my eye. I do not mean that assuming the wheels had a logo, the logo is pointing in the same direction for both whe...

- Mon Aug 13, 2007 11:01 pm UTC
- Forum: Science
- Topic: Synchronized wheels
- Replies:
**13** - Views:
**3125**

### Synchronized wheels

Every once in a while I'll notice on certain cars that as they roll to a stop their front and rear wheels appear perfectly synchronized. This is only with certain cars though (usually the nicer ones). It has nothing to do with whether the wheels are on the same phase or not. What is the explanation ...

- Sat Aug 11, 2007 11:57 pm UTC
- Forum: Mathematics
- Topic: Natural complements - C and S
- Replies:
**29** - Views:
**4174**

- Thu Aug 09, 2007 4:58 pm UTC
- Forum: Mathematics
- Topic: Capital letter pi
- Replies:
**25** - Views:
**6524**

- Wed Aug 08, 2007 4:29 pm UTC
- Forum: Mathematics
- Topic: Proving something by proving its unprovable.
- Replies:
**25** - Views:
**5901**

- Wed Aug 08, 2007 2:25 am UTC
- Forum: Mathematics
- Topic: Percentage of reals rational
- Replies:
**74** - Views:
**12705**

- Wed Aug 08, 2007 1:32 am UTC
- Forum: Mathematics
- Topic: Proving something by proving its unprovable.
- Replies:
**25** - Views:
**5901**

not to derail the course of the thread (yeah right) but what is the precise definition of enumerate in the mathematical sense? The definitions I am familiar with are 1. Ascertain the number of something 2. To name the elements of a list one by one In which case the answer to the original axiom quest...

- Tue Aug 07, 2007 6:57 pm UTC
- Forum: Mathematics
- Topic: Proving something by proving its unprovable.
- Replies:
**25** - Views:
**5901**

What do you mean? You wouldn't stop. There are infinitely many possible axioms after all... This is my point... You can't do it. Well, the main target of Godel was Peano Arithmetic, which is the theory of the natural numbers with addition and multiplication, the successor function, and the usual or...

- Tue Aug 07, 2007 6:01 pm UTC
- Forum: Mathematics
- Topic: Proving something by proving its unprovable.
- Replies:
**25** - Views:
**5901**

How would you know when to stop? Godel's incompleteness theorem affects systems with sufficient expressive power. I would also like to know what the use of sufficiently weak systems would be. As far as the irrational behaviour of humans, well, once you have a system that asserts something false, the...

- Tue Aug 07, 2007 3:53 pm UTC
- Forum: Mathematics
- Topic: Proving something by proving its unprovable.
- Replies:
**25** - Views:
**5901**

- Mon Aug 06, 2007 9:58 pm UTC
- Forum: Mathematics
- Topic: GRE Math
- Replies:
**40** - Views:
**6017**

The GMAT study book I ordered from the library finally arrived, and when I got home and opened it up I was pissed. It was only a book on the math section of the standard GRE. Which also happens to help you with the GMAT. Except that it doesn't. Anyway, if you find any study guides that are more rece...

- Mon Aug 06, 2007 5:50 pm UTC
- Forum: Mathematics
- Topic: GRE Math
- Replies:
**40** - Views:
**6017**

- Fri Aug 03, 2007 10:39 pm UTC
- Forum: Mathematics
- Topic: Percentage of reals rational
- Replies:
**74** - Views:
**12705**

- Fri Aug 03, 2007 5:59 pm UTC
- Forum: Mathematics
- Topic: using metric spaces as transformations
- Replies:
**3** - Views:
**1461**

- Fri Aug 03, 2007 5:27 pm UTC
- Forum: Mathematics
- Topic: Percentage of reals rational
- Replies:
**74** - Views:
**12705**

- Fri Aug 03, 2007 5:24 pm UTC
- Forum: Mathematics
- Topic: using metric spaces as transformations
- Replies:
**3** - Views:
**1461**

### using metric spaces as transformations

I'm just learning about metric spaces and I've been thinking a bit about the possibility of using a different metrics as a transformation. Could a change to a different metric be useful in solving problems? I'm thinking along the lines of how using LaPlace transforms simplifies certain problems for ...

- Tue Jul 31, 2007 8:13 pm UTC
- Forum: Mathematics
- Topic: The cocky exponential function e^x
- Replies:
**6** - Views:
**3073**

- Fri Jul 27, 2007 5:49 pm UTC
- Forum: Mathematics
- Topic: multiplying integrals
- Replies:
**2** - Views:
**2801**

- Fri Jul 27, 2007 4:51 pm UTC
- Forum: Mathematics
- Topic: multiplying integrals
- Replies:
**2** - Views:
**2801**

### multiplying integrals

Crap, studying for my intro to analysis class and I can't remember how this works. Deriving int(0 to infinity)[e^(-x^2)]dx So we call this integral I then I^2 = int(0 to infinity)[e^(-x^2)]dx*int(0 to infinity)[e^(-y^2)]dy = int(0 to infinity)[int(0 to pi/2)[e^(-r^2)rdrdθ using the transformati...

- Thu Jul 26, 2007 6:06 pm UTC
- Forum: Mathematics
- Topic: Strange math thought (grid related)
- Replies:
**21** - Views:
**3546**

- Tue Jul 24, 2007 4:43 am UTC
- Forum: Mathematics
- Topic: The mathmatics of pizza:
- Replies:
**74** - Views:
**11346**

I remember going to a McDonalds once and noticing that the 20 Chicken McNuggets item cost more than five times as much as the 4 Chicken McNuggets item. I went to burger king once and they wouldn't serve us because we walked up to the drive-through window. They also should've kept a padlock on the m...

- Tue Jul 24, 2007 4:41 am UTC
- Forum: Mathematics
- Topic: most efficient base for prime number searching
- Replies:
**9** - Views:
**3036**

But hexadecimal is translatable, and, in fact, I suspect greatly that it's easier to translate that decimal. Perhaps it's more difficult because people don't like to think of how many E's something is divisible by. Of course it's easier to translate than decimal. You would think if it helped you fi...

- Mon Jul 23, 2007 10:22 pm UTC
- Forum: Mathematics
- Topic: most efficient base for prime number searching
- Replies:
**9** - Views:
**3036**

2. Then you can let your computer do it. ;) Actually, this brings up a good point - any divisibility tests that would help you out in other bases would have to be translated to binary anyway for your computer to churn it out. For instance what Cosmologicon mentioned. My guess is that certain tests ...

- Mon Jul 23, 2007 3:56 pm UTC
- Forum: Mathematics
- Topic: Larger than Clarkkkson?
- Replies:
**11** - Views:
**2807**

- Mon Jul 23, 2007 4:49 am UTC
- Forum: Mathematics
- Topic: most efficient base for prime number searching
- Replies:
**9** - Views:
**3036**

### most efficient base for prime number searching

I just read that hexadecimal is less efficient than decimal, which led to the following question: Which is the most efficient base for searching for prime numbers?

- Sat Jul 21, 2007 6:53 pm UTC
- Forum: Mathematics
- Topic: Probability
- Replies:
**9** - Views:
**2438**

- Sat Jul 21, 2007 6:48 pm UTC
- Forum: Mathematics
- Topic: GRE Math
- Replies:
**40** - Views:
**6017**

I guess I had just forgotten the definition of a vector space. I was thinking along the lines of region where you can have two regions of the same dimension but never intersect. OK, so what about in a 3 dimensional vector space, lets say you have 2 subspaces of 2 dimensions, V1 and V2. What if V1 an...

- Sat Jul 21, 2007 1:06 am UTC
- Forum: Mathematics
- Topic: GRE Math
- Replies:
**40** - Views:
**6017**

haha, yeah, I asked that then I realized it was a dumb question. My mind was fried from doing all the questions. I had a fun time doing them too though. Gotta catch up on my linear algebra, well not really, but the 6 dimensional vector subspaces in a 10 dimensional vector space threw me off. When it...

- Fri Jul 20, 2007 11:47 pm UTC
- Forum: Mathematics
- Topic: GRE Math
- Replies:
**40** - Views:
**6017**

### GRE Math

I'm getting ready to take the GRE Math test. Any advice on how to prepare? Looks fairly straightforward from the practice test but it looks like she can be a bitch in a few places.

http://www.ets.org/Media/Tests/GRE/pdf/Math.pdf

http://www.ets.org/Media/Tests/GRE/pdf/Math.pdf

- Thu Jul 19, 2007 5:21 pm UTC
- Forum: Mathematics
- Topic: Really huge numbers
- Replies:
**30** - Views:
**4486**

- Thu Jul 19, 2007 4:14 pm UTC
- Forum: Mathematics
- Topic: Really huge numbers
- Replies:
**30** - Views:
**4486**

- Tue Jul 17, 2007 6:39 pm UTC
- Forum: Mathematics
- Topic: Favourite Erroneous "Proofs"
- Replies:
**194** - Views:
**43831**

I saw a geometric proof once that every angle was a right angle, which I enjoyed very much. I think it's pretty well known; a version of it may be found here . Can I get a little help here? It seems to me that the error comes in with doing angle subtraction on dissimilar parts of congruent triangle...

- Tue Jul 17, 2007 1:55 am UTC
- Forum: Science
- Topic: Science in the bible
- Replies:
**160** - Views:
**17058**

Ok anything in the bible that is against our current sciences is BULL Anything in the bible that isn't against our current sciences is as true as any other thing that isn't against our current sciences that we could claim about thousands of years ago. Point: Bible is Bull. True for other religious ...

- Mon Jul 16, 2007 11:50 pm UTC
- Forum: Mathematics
- Topic: Really huge numbers
- Replies:
**30** - Views:
**4486**

- Mon Jul 16, 2007 10:13 pm UTC
- Forum: Mathematics
- Topic: Really huge numbers
- Replies:
**30** - Views:
**4486**

- Mon Jul 16, 2007 3:46 pm UTC
- Forum: Mathematics
- Topic: Can't find a proof
- Replies:
**7** - Views:
**1865**

- Thu Jul 12, 2007 7:21 pm UTC
- Forum: Mathematics
- Topic: Percentage of reals rational
- Replies:
**74** - Views:
**12705**

For simplicity, let's just work with [0,1]. The rationals in this interval are countable, so assume that the complete list of rationals is q_1, q_2, q_3, etc. Now the first step of the random generator method is to flip an infinite sequence of coins. If the first coin comes up tails, then the rando...