Search found 2883 matches

by Eebster the Great
Sun May 09, 2010 4:25 pm UTC
Forum: Coding
Topic: Confusing calculations for finding a diagonal
Replies: 3
Views: 618

Re: Confusing calculations for finding a diagonal

I assume you meant: CALC b a * a CALC c sqrt( ( b * 2 ) + b ) CALC d c / 2 Rounding in the middle of a calculation makes the calculated intermediate result wrong by a small amount. If the next operations in the calculation involve multiplying (or squaring), then the error is similarly multiplied an...
by Eebster the Great
Sun May 09, 2010 7:28 am UTC
Forum: Coding
Topic: Confusing calculations for finding a diagonal
Replies: 3
Views: 618

Confusing calculations for finding a diagonal

So I am performing a molecular dynamics run for senior project, and am basically taking and modifying a script. At one point, it calculates the variable for the longest diagonal of a rhombic dodecahedral box (don't ask why they use that shape) from another length, and it requires multiplying by \fra...
by Eebster the Great
Sat May 08, 2010 10:33 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

That's problematic to me - what about conservation laws? Where does the charge go? Why doesn't density change along with the apparent length? Conservation and invariance are different. For example, energy is conserved, because it never changes within one reference frame, but it is not invariant, be...
by Eebster the Great
Sat May 08, 2010 4:19 am UTC
Forum: Language/Linguistics
Topic: Think Before Naming Your Child
Replies: 1622
Views: 311494

Re: Think Before Naming Your Child

tastelikecoke wrote:I kind of feel sorry for those who's nick name is Dick.

It's better than the name Athol.
by Eebster the Great
Fri May 07, 2010 7:23 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

No, these are distinct situations. A quantum state always obeys CPT symmetry exactly. It does not always give you an exact single constant for E. It gives you a wavefunction whose derivative is E and which obeys CPT. The distribution respects energy conservation exactly , and in the same way it res...
by Eebster the Great
Fri May 07, 2010 7:14 pm UTC
Forum: Mathematics
Topic: Favorite math jokes
Replies: 1452
Views: 457687

Re: Favorite math jokes

WTF? In case you weren't aware, "A topologist is someone who doesn't know his ass from a hole in the ground" is a somewhat famous joke. If by famous I mean nobody has ever actually heard it unless they are a topologist or xkcdian. And in case you weren't aware there was a post directly pr...
by Eebster the Great
Fri May 07, 2010 5:08 am UTC
Forum: Mathematics
Topic: Favorite math jokes
Replies: 1452
Views: 457687

Re: Favorite math jokes

kaimason1 wrote:WTF?

In case you weren't aware, "A topologist is someone who doesn't know his ass from a hole in the ground" is a somewhat famous joke. If by famous I mean nobody has ever actually heard it unless they are a topologist or xkcdian.
by Eebster the Great
Fri May 07, 2010 5:00 am UTC
Forum: Language/Linguistics
Topic: Think Before Naming Your Child
Replies: 1622
Views: 311494

Re: Think Before Naming Your Child

The Scyphozoa wrote:There's a person named Vietnam Nguyen. That's just weird.

Well Nguyen is by far the most common Vietnamese surname, so if you're going to go by "Vietnam," I guess it's the name to have.

But I prefer Hui Nguyen. Apparently there is a facebook group for people by that name.
by Eebster the Great
Fri May 07, 2010 4:57 am UTC
Forum: Mathematics
Topic: Proof by Contradiction
Replies: 25
Views: 2648

Re: Proof by Contradiction

jestingrabbit: So undergrad is only three years in Australia? Maybe I should move there ;). What do you need for a PhD.? In the US it's typically four years of undergrad (which most people would start immediately after graduating from high school, or perhaps one year later) followed by 3-4 years gra...
by Eebster the Great
Fri May 07, 2010 4:46 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

Au contraire, mon frer. CPT is totally exact in QFT, eg. Yes, but it is only exact for the probability distribution, not for the "actual quantum state," whatever that means. Why are you not sure what a quantum mechanical state is? CPT holds for any and every state. My point was that the q...
by Eebster the Great
Fri May 07, 2010 4:43 am UTC
Forum: Mathematics
Topic: Pondering a Potential function (Does it exist)
Replies: 12
Views: 1341

Re: Pondering a Potential function (Does it exist)

I said "Is there a function which <does this stuff>", not "is there a function <which has some properties>". There is a difference. The former implies that you are explicitly defining its action on objects, either as a rule or on an element-by-element basis. Fine. "Is there...
by Eebster the Great
Thu May 06, 2010 12:04 am UTC
Forum: Mathematics
Topic: Proof by Contradiction
Replies: 25
Views: 2648

Re: Proof by Contradiction

In the UK we get taught from year 1 to year 11 (normally spread over two schools called primary school and secondary school, sometimes three) which you finish at 16 years old. That's the end of our compulsory education. The vast majority of people then go on to college education (called sixth-form ...
by Eebster the Great
Thu May 06, 2010 12:01 am UTC
Forum: Science
Topic: So, quick question. (Earth stopped in its tracks)
Replies: 103
Views: 7745

Re: So, quick question. (Earth stopped in its tracks)

I think the problem people are having is that we don't really know what it means for the Earth to "stop in its tracks," since in reality, things are gradually decelerated by external forces, they don't just automagically stop on a dime. It is difficult to give any conclusive statements of ...
by Eebster the Great
Wed May 05, 2010 11:58 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

Au contraire, mon frer. CPT is totally exact in QFT, eg. Yes, but it is only exact for the probability distribution, not for the "actual quantum state," whatever that means. Similarly, conservation of energy applies only for the probability distribution of energies (if that is the correct...
by Eebster the Great
Wed May 05, 2010 3:11 am UTC
Forum: Science
Topic: Naturalness of homosexual behavior
Replies: 41
Views: 6505

Re: Naturalness of homosexual behavior

everyone please raise your hand for renaming the birthday paradox the lesbian paradox? Nah, the math doesn't work the same way, because the lesbian "paradox" is like finding that two given people happened to both be born specifically in January, rather than that some pair of people out of...
by Eebster the Great
Wed May 05, 2010 3:08 am UTC
Forum: Mathematics
Topic: Need some understanding.
Replies: 13
Views: 1855

Re: Need some understanding.

Hopital bought the theorem. Unlike Möbius, who earned the use of the Umlaut, I don't think paying a mathematician to name a theorem after you is worthy of bothering with character codes. :) http://en.wikipedia.org/wiki/L%27Analyse_des_Infiniment_Petits_pour_l%27Intelligence_des_Lignes_Courbes Ah, b...
by Eebster the Great
Wed May 05, 2010 3:05 am UTC
Forum: Mathematics
Topic: Pondering a Potential function (Does it exist)
Replies: 12
Views: 1341

Re: Pondering a Potential function (Does it exist)

That is, by simply saying "Does a function which <does this stuff> exist?", you have created the function which <does this stuff>. Well, so long as you make sure that it's well-defined. Well, no, because you could be describing a relation that is not a function. For example, I could say, ...
by Eebster the Great
Wed May 05, 2010 2:55 am UTC
Forum: Mathematics
Topic: Proof by Contradiction
Replies: 25
Views: 2648

Re: Proof by Contradiction

This thread seems solved, but yr 12= 16-17= 1st year of sixth form = year before being a senior in high school in the US (I think... you guys have your high school until 18, right?) Man, the British educational system just confuses me every time I try to understand it. To clarify, how many differen...
by Eebster the Great
Tue May 04, 2010 7:11 am UTC
Forum: Science
Topic: Naturalness of homosexual behavior
Replies: 41
Views: 6505

Re: Naturalness of homosexual behavior

Or, just very coincidental. Yeah, that. If lesbians account for even a conservative 5% of the population, you'd expect two randomly selected women to both be lesbians 1/400 of the time. Considering the number of people we all know, I'd say the unusual thing would be if no one posting in this thread...
by Eebster the Great
Tue May 04, 2010 6:49 am UTC
Forum: Mathematics
Topic: Proof by Contradiction
Replies: 25
Views: 2648

Re: Proof by Contradiction

Starfox444 wrote:I'm afraid I'm not familiar with this. Only a year 12 student after all, don't use that sort of thing. Could you word your statement differently?
Thanks for the quick response and effort.

As somebody who has never lived in Britain or Canada . . . what does that mean?
by Eebster the Great
Tue May 04, 2010 6:32 am UTC
Forum: Mathematics
Topic: Need some understanding.
Replies: 13
Views: 1855

Re: Need some understanding.

dean.menezes wrote:Also "L'Hôspital's rule" has an circumflex on the o.

Don't you mean "L'Hôpital's rule?"
by Eebster the Great
Tue May 04, 2010 6:27 am UTC
Forum: Mathematics
Topic: Visualizing higher dimensions
Replies: 2
Views: 580

Re: Visualizing higher dimensions

It sounds like you are not having trouble imagining four dimensions, but three. This is harder than it sounds.

For four dimensions, try imagining a three-dimensional object evolving over time.
by Eebster the Great
Tue May 04, 2010 6:26 am UTC
Forum: Mathematics
Topic: Pondering a Potential function (Does it exist)
Replies: 12
Views: 1341

Re: Pondering a Potential function (Does it exist)

Is it just me, or is the signum function kind of like the Heaviside function but not as useful?
by Eebster the Great
Tue May 04, 2010 6:18 am UTC
Forum: Mathematics
Topic: Favorite math jokes
Replies: 1452
Views: 457687

Re: Favorite math jokes

by Eebster the Great
Tue May 04, 2010 2:03 am UTC
Forum: Science
Topic: So, quick question. (Earth stopped in its tracks)
Replies: 103
Views: 7745

Re: So, quick question. (Earth stopped in its tracks)

I suspect the intended meaning was to get off of it *before* the planet stops, rather than when it stops. My point was that you'd have to stay on it, trying to renter would be silly because you're just going to fall into the sun anyway, and you have a more-or-less free ride off the surface, assumin...
by Eebster the Great
Tue May 04, 2010 1:58 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

If that's what you mean by conservation of energy, that the distribution of energies is conserved, then I have no qualms. But I think perhaps if you told Lagrange that's what energy conservation meant, he might have his own set of bones for you. Lol, well Lagrange was a classical physicist. I'm not...
by Eebster the Great
Sun May 02, 2010 8:57 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

You can use some interpretive hoop jumping to keep fundamental indeterminacy and observer ignorance distinct at the quantum level, but you certainly don't have to. For most they are identical. It doesn't matter whether or not they are the same. Constants can still be fundamentally indeterminate. En...
by Eebster the Great
Sun May 02, 2010 8:42 pm UTC
Forum: Logic Puzzles
Topic: luinis: html game
Replies: 88
Views: 13063

Re: luinis: html game

Without wanting to make it too blatantly obvious: What numbers do the letters o and z look like? Don't click unless you seriously seriously want the fun of number 20 ruined, because it's all but giving you the answer. Uh no, I also thought that was obvious. I am really not getting this. Never mind,...
by Eebster the Great
Sun May 02, 2010 8:41 pm UTC
Forum: Logic Puzzles
Topic: luinis: html game
Replies: 88
Views: 13063

Re: luinis: html game

SlyReaper wrote:Without wanting to make it too blatantly obvious:

Spoiler:
What numbers do the letters o and z look like?


Don't click unless you seriously seriously want the fun of number 20 ruined, because it's all but giving you the answer.


Uh no, I also thought that was obvious. I am really not getting this.
by Eebster the Great
Sat May 01, 2010 7:06 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

Wait, are you claiming that the total energy of a closed system is some kind of hidden variable? *SIGH* This has nothing to do with hidden variable theories. It has to do with the distinction between violating conservation of energy and summing all possible histories to obtain a range of uncertaint...
by Eebster the Great
Sat May 01, 2010 7:05 pm UTC
Forum: Logic Puzzles
Topic: luinis: html game
Replies: 88
Views: 13063

Re: luinis: html game

dracojames wrote:For number 20 (the hint being:)
Spoiler:
oz


I'll give you the advice someone else gave me:
Spoiler:
like it says, don't use the internet; instead, try a mirror


Yeah, I saw that. I tried everything I could think of involving the clue, that hint, and the number 20. I seriously don't get it.
by Eebster the Great
Sat May 01, 2010 7:20 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

Yeah, I don't recall doogly ever saying anything about borrowing energy for a short time, so please stop arguing as if he did. He said this: You can use quantum mechanics to violate conservation of energy on very short timescales. And: Griffiths is totally wrong. Both of which are wrong. You cannot...
by Eebster the Great
Sat May 01, 2010 7:02 am UTC
Forum: Logic Puzzles
Topic: luinis: html game
Replies: 88
Views: 13063

Re: luinis: html game

For getting to 19, from 18 The hint for 18 is Ovid Is dead. Consider how this relates to the number of the page it is on. Or, in more detail: Specifically, if Ovid relates to the #18 in some way, then what relates to the number 19 in a similar way? and Go back to SlyReaper's hint "When did...
by Eebster the Great
Fri Apr 30, 2010 5:22 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

Griffiths is totally wrong. Classical conservation of energy says that E is a constant. If it is a constant, \Delta E = 0 . QM says this is not OK. Griffiths could at most say "I don't find the borrowing analogy helpful." This I wouldn't argue with. Perhaps Dr. Wikipedia will convince you...
by Eebster the Great
Fri Apr 30, 2010 4:06 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0734: "Outbreak"
Replies: 126
Views: 26062

Re: "Outbreak" Discussion

The Origamist wrote:Why are they numbering their patients starting at zero?

It's a commonly used term for the origin of new diseases or disease outbreaks.
by Eebster the Great
Wed Apr 28, 2010 11:57 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2863
Views: 626751

Re: RELATIVITY QUESTIONS! (and other common queries)

BlackSails wrote:You cant overthrow thermodynamics without also overthrowing every other bit of science. Thermodynamics is the bedrock.

Wouldn't QM logically be the bedrock? QM and statistics should yield thermodynamics (in principle).
by Eebster the Great
Tue Apr 27, 2010 9:46 pm UTC
Forum: Science
Topic: So, quick question. (Earth stopped in its tracks)
Replies: 103
Views: 7745

Re: So, quick question. (Earth stopped in its tracks)

Tass wrote:Fungi would spread, though, until the cold killed them.

Or until they ran out of food; whichever happened first.
by Eebster the Great
Tue Apr 27, 2010 4:20 am UTC
Forum: Science
Topic: So, quick question. (Earth stopped in its tracks)
Replies: 103
Views: 7745

Re: So, quick question. (Earth stopped in its tracks)

With the photosynthesizers out of the way, chemosysthesis would be viable all over the place. It's only being out competed by those damn cheaters that's been holding them back. It'd be like the good ole days again, about three billion years ago! Only darker. No it wouldn't. Most chemosynthetic orga...
by Eebster the Great
Tue Apr 27, 2010 4:04 am UTC
Forum: Science
Topic: Fun with magnetic flux sensors
Replies: 6
Views: 572

Re: Fun with magnetic flux sensors

Couldn't it just be the hard drive? Just a thought.
by Eebster the Great
Tue Apr 27, 2010 4:01 am UTC
Forum: Science
Topic: update me on evolution theory?
Replies: 23
Views: 2495

Re: update me on evolution theory?

The first development of momentous significance since The Origin of Species was undoubtedly Mendel's genetic theory. What is typically called the "Theory of Evolution" is sometimes called "Modern Evolutionary Synthesis," since it represents the synthesis of the concept of natural...

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