## Search found 26 matches

Mon Sep 26, 2011 3:52 am UTC
Forum: Mathematics
Topic: Question on Formal Rational Functions
Replies: 5
Views: 1320

### Re: Question on Formal Rational Functions

Thank you all. I got more than I asked for, but it was a nice diversion. I was interested in disproving the Nested Interval Theorem with the formal rational functions as your field, and, I guess, thinking about whether this was true for non-Archimedean fields in general. I found a counter example to...
Sun Sep 25, 2011 11:47 pm UTC
Forum: Mathematics
Topic: Question on Formal Rational Functions
Replies: 5
Views: 1320

### Question on Formal Rational Functions

Most definitions I see of Formal Rational Functions are fairly informal. My Real Analysis text's brief mentioning of them goes "The formal rational functions are the usual quotients of polynomials, but we don't concern ourselves with the annoying details like their domains. For instance \frac{7...
Fri Mar 18, 2011 1:33 pm UTC
Forum: Mathematics
Topic: Derivative (chain rule?), ex. w.r.t. the Gauss map
Replies: 3
Views: 1049

### Re: Derivative (chain rule?), ex. w.r.t. the Gauss map

Both help a lot. Thank you very much.
Fri Mar 18, 2011 3:40 am UTC
Forum: Mathematics
Topic: Derivative (chain rule?), ex. w.r.t. the Gauss map
Replies: 3
Views: 1049

### Derivative (chain rule?), ex. w.r.t. the Gauss map

In general how do we differentiate g(f) when g'(f)*f', i.e. the chain rule, yields an f not in the domain of g' within g'? The Gauss map is such a g since it is from a surface to the unit sphere, but its derivative is to and from a tangent-plane of the surface. Typical chain-rule (as taught in calcu...
Sun Jan 17, 2010 10:21 pm UTC
Forum: Science
Topic: E&M/Relativity Problem. Solenoid by current planes
Replies: 4
Views: 957

### Re: E&M/Relativity Problem. Solenoid by current planes

Ah right. Yeah knew the electric field as result of movement/length contraction, totally bollocks'd up the constant field thing though. And my diagram too looking back. Danke
Sun Jan 17, 2010 12:42 am UTC
Forum: Science
Topic: E&M/Relativity Problem. Solenoid by current planes
Replies: 4
Views: 957

### Re: E&M/Relativity Problem. Solenoid by current planes

Thank you very much for the answer. I know that there is an electric field inherent with the dΦ/dt. I'm trying to see where the other electric field comes from (the plate or magnetic field are the only things I see that could possibly cause this Efield as from the Solenoid's POV it isn't moving but ...
Sat Jan 16, 2010 1:19 pm UTC
Forum: Forum Games
Topic: Do you have one too.
Replies: 127
Views: 18008

### Re: Do you have one too.

Shame no one had the watch. Anyway,
I have a rainbow hacky sack.
Sat Jan 16, 2010 12:39 am UTC
Forum: Forum Games
Topic: Count to a Million
Replies: 92958
Views: 7142832

### Re: Count to a Million

22934
Fri Jan 15, 2010 11:59 pm UTC
Forum: General
Topic: Thoughts for ships
Replies: 90163
Views: 8910126

### Re: Fleeting/Random/Thoughts (Random like the plague)

My dog has a brain. He is another creature, and it thinks. Another thing is sentient, and it is furry, and is flapping with its tongue. And it's so much different than me, but it has a brain like me. Sorry. Ever just have one of those perspective moments were something about nature amazes you? Like ...
Fri Jan 15, 2010 11:47 pm UTC
Forum: Forum Games
Topic: Count to a Million
Replies: 92958
Views: 7142832

### Re: Count to a Million

22931
Fri Jan 15, 2010 11:38 pm UTC
Forum: Science
Topic: E&M/Relativity Problem. Solenoid by current planes
Replies: 4
Views: 957

### E&M/Relativity Problem. Solenoid by current planes

Situation: Their are two parallel, infinite plates of current (ignore the force of one on another). Near one of them is a solenoid (in simple circuit) held such that the magnetic field lines from the plates go straight through it (remember Bfield lines from plates are parallel). Now this solenoid be...
Tue Jan 12, 2010 5:26 pm UTC
Forum: Forum Games
Topic: Count to a Million
Replies: 92958
Views: 7142832

### Re: Count to a Million

22769
Sat Jan 09, 2010 5:34 pm UTC
Forum: Language/Linguistics
Topic: Dichotic Listening Tests
Replies: 5
Views: 3619

### Dichotic Listening Tests

Hi looking for a dichotic listening test other than http://www.linguistics.ucla.edu/people/schuh/lx001/Dichotic/dichotic.html . I took this one and got some pretty odd results and want to take a different one. I took Ling 105 so I know something about neurolinguistics. Anyway hopefully someone wiser...
Tue Jan 05, 2010 6:17 pm UTC
Forum: Forum Games
Topic: Do you have one too.
Replies: 127
Views: 18008

### Re: Do you have one too.

After a small piece of tape and a fifty dollar bill: yes, I do have a shirt with my name on it.
Do you have a pinata in your room?
Tue Jan 05, 2010 6:08 pm UTC
Forum: Forum Games
Topic: Count to a Million
Replies: 92958
Views: 7142832

### Re: Count to a Million

22493
Mon Nov 16, 2009 2:09 am UTC
Forum: Science
Topic: Entropy related hw question. Showing Sab=Sa+Sb
Replies: 3
Views: 545

### Re: Entropy related hw question. Showing Sab=Sa+Sb

I agree with what you said mathematically but I don't see where you multiply partition functions. Note: my class hasn't used the term "partition function" yet, but from what wiki has I think it/you mean is the entropy, and I'm adding the entropy of A and entropy of B, and the log functions...
Mon Nov 16, 2009 1:25 am UTC
Forum: Science
Topic: Entropy related hw question. Showing Sab=Sa+Sb
Replies: 3
Views: 545

### Entropy related hw question. Showing Sab=Sa+Sb

"Show that S ab =S a +S b follows from the definition of entropy." Earlier in chapter "we define entropy as S=K b ln(Ω)" I tried to show it by saying: S ab =S a +S b =K b (ln(Ω a *Ω b ) ∴ Ω a *Ω b =Ω ab And using Ω=(q+N-1)!/(q!(N-1)! that's wrong. Where q is the amount of energy ...
Sat Nov 07, 2009 12:13 am UTC
Forum: Mathematics
Topic: Cubic blocks question (Analysis) [Homework]
Replies: 26
Views: 1786

### Re: Cubic blocks question (Analysis) [Homework]

I like this problem. I wish I had a bag of those cubes to play with. :) I wonder what is the volume of the smallest cube (or rectangular box) that can contain the block collection? Or, if that's too hard, it'd be nice to have some sort of indication of the maximum packing density. My intuition tell...
Tue Feb 24, 2009 2:43 am UTC
Forum: Logic Puzzles
Topic: Some fun ones
Replies: 17
Views: 2158

### Re: Some fun ones

All right, this one's not in really the same vein as the other puzzles here, but I started this thread and I hereby allow myself to post a puzzle that is not so much a trick as a real 'problem', because virtualluy any puzzle can be a 'fun one'. Find a four digit number whose square ends in the numb...
Mon Dec 01, 2008 10:37 pm UTC
Forum: Science
Topic: "Negative" Gravity? (Stop cringing, physics majors!)
Replies: 20
Views: 3224

### Re: "Negative" Gravity? (Stop cringing, physics majors!)

Say, for instance (in two dimensions for simlicity), we have a heavy object on the right, which spontaneously at some point moves over to the left, then back over to the right again where it started. Then it sits still again. Now, an observer someways above all this action would feel gravity down-a...
Mon Dec 01, 2008 3:47 am UTC
Forum: General
Topic: Making a fireball
Replies: 8
Views: 1407

### Making a fireball

***See post below, same vid. diff. website*** I gotta try that. Also, one can light a puddle of rubbing alcohol on their hands and not get burned since the fumes, not the liquid itself, are what burn. As the guy says, be safe. edit: Thanks dude for letting me know the 404. You got the same video but...
Mon Dec 01, 2008 3:32 am UTC
Forum: Science
Topic: Effectiveness of lower D. analogies to explain Higher D.s
Replies: 3
Views: 895

### Effectiveness of lower D. analogies to explain Higher D.s

In a discussion about gravity earlier today ( "Negative" Gravity? (Stop cringing, physics majors!) ) it was brought up how space time is like a rubber sheet, and I drew the analogy of a rubber band with a mass on it. But some points were brought up against the effectiveness of describing s...
Mon Dec 01, 2008 2:19 am UTC
Forum: Science
Topic: "Negative" Gravity? (Stop cringing, physics majors!)
Replies: 20
Views: 3224

### Re: "Negative" Gravity? (Stop cringing, physics majors!)

Yes but choosing to have the mass disappear makes the situation easier to picture. The rules should all be the same. If I take a mass and roll the mass across a rubber band there are minute waves along the entire band, but it'll still follow the same laws if I suddenly pick up the mass... I don't se...
Mon Dec 01, 2008 1:52 am UTC
Forum: Science
Topic: "Negative" Gravity? (Stop cringing, physics majors!)
Replies: 20
Views: 3224

### Re: "Negative" Gravity? (Stop cringing, physics majors!)

I by no means know the answer but: based on the theory that gravity acts in 3Dspace-time similarly to how mass affects a 2D sheet then the force is based on the way the sheet bends: If you assume the disappearance of the sun would create a ripple in this 4D sheet then as the wave hit an object the o...
Mon Dec 01, 2008 1:34 am UTC
Forum: Music
Topic: Top 10 Artists
Replies: 248
Views: 157893

### Re: Top 10 Artists

Metallica
Amon Amarth
Dethklok
Behemoth
The Absense
Heaven Shall Burn
Ash and Elm (A band I can say you haven't heard of)
Led Zeppelin
Blind Guardian

Top artists is easy, top songs is hard. I couldn't name any of my top five, I love 'em all so much.
Mon Dec 01, 2008 12:53 am UTC
Forum: Science
Topic: You might be a physics major if...
Replies: 540
Views: 61908

### Re: You might be a physics major if...

... on a rainy day you construct a catapult only with materials you find in your bed room.
... when you lay down and look at clouds you start thinking about flow and liquid mechanics, regardless of how hard you try not to.