## Search found 2214 matches

- Sun Dec 01, 2013 4:31 pm UTC
- Forum: Mathematics
- Topic: Number of different sets of prizes
- Replies:
**6** - Views:
**1604**

### Re: Number of different sets of prizes

Either that or it's one of a small set of problems for which you get plenty of time. A bit of (re-)factoring makes the calculation doable: 15!/8!/7! = 15*14*13*12*11*10*9/(7*6*5*4*3*2) = 15*14*13*12*11*10*9/(7*6*5*3*2*2*2) = 15*14*13*12*11*10*9/(14*12*10*3) = 15*13*11*9/3 = 15*13*33 ...although I ha...

- Sat Nov 30, 2013 2:39 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1292: Pi vs. Tau
- Replies:
**124** - Views:
**30036**

### Re: 1292: Pi vs. Tau

25% of the time (when the digit originated in pi and there's no carry) 1 is followed by 2 even assuming a 1 from tau n is never followed by a 2 from pi n+1 (this in not true), one is followed by 2 more than ten percent of the time, which makes pi-interleaved-tau not normal. That finally made me loo...

- Fri Nov 29, 2013 2:27 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1292: Pi vs. Tau
- Replies:
**124** - Views:
**30036**

### Re: 1292: Pi vs. Tau

OK, as a proportion it would tend to zero in my example, although in absolute terms there would be a bias forever. I think you've picked up on what I was getting at, i.e. the two numbers are related so there could be a systematic bias even if they're both normal. Indeed there is some bias. If you g...

- Fri Nov 29, 2013 1:52 am UTC
- Forum: Site/Forum issues
- Topic: Forum is very very very slow
- Replies:
**69** - Views:
**36636**

### Re: Forum is very very very slow

davean wrote:Yah, well, they keep changing how they are attacking.

That's a bummer.

Either way, keep up the good work against the bots.

- Wed Nov 27, 2013 2:21 pm UTC
- Forum: Mathematics
- Topic: comparing big numbers by hand
- Replies:
**7** - Views:
**1817**

### Re: comparing big numbers by hand

I would probably just calculate the answer. With addition-chain exponentiation you can get 3³³ = 3² ² ² ² ²×3 with 6 multiplications. Also, take a look at what powers of 3, 4 and 5 get close to 10 x . (you can use any base you like, but most people are better at estimating in base 10) Spoilered is t...

- Wed Nov 27, 2013 1:42 pm UTC
- Forum: Science
- Topic: 3D visual perception
- Replies:
**40** - Views:
**6723**

### Re: 3D visual perception

Thanks for the responses so far. :) I guess it's not possible (avoiding brain interfaces for a moment) because our retina is surface-like and not a volume. This is pretty much how it is, and always will be. Having a 3D retina wouldn't help. Depth comes from cues such as parallax, shading, and probab...

- Wed Nov 27, 2013 5:43 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1296: "Git Commit"
- Replies:
**49** - Views:
**10578**

### 1296: "Git Commit"

http://imgs.xkcd.com/comics/git_commit.png Pop-up text: " Merge branch 'asdfasjkfdlas/alkdjf' into sdkjfls-final " This is so very true. If you're committing at a fast pace (especially when debugging a school project) the comments are often jibberish. That, or no comment at all, if the CV...

- Tue Nov 26, 2013 1:07 pm UTC
- Forum: Science
- Topic: 3D visual perception
- Replies:
**40** - Views:
**6723**

### 3D visual perception

Hi guys, in the maths board there's (yet another) discussion on 4D and it made me wonder whether it's possible for us to acquire 3-dimensional vision * in a (virtual) 4-dimensional space. Searches on the subject got me interesting results (among all the 3-dimensional TVs), but none are about 3-dimen...

- Sun Nov 24, 2013 10:31 am UTC
- Forum: Mathematics
- Topic: Check result-condition number
- Replies:
**6** - Views:
**1763**

### Re: Check result-condition number

evinda wrote:Why is my result so different from yours????

Did you not notice the little / in the middle?

The only difference is that you got ~5 digits of accuracy and Nathan got the exact result.

- Sun Nov 24, 2013 10:26 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1292: Pi vs. Tau
- Replies:
**124** - Views:
**30036**

### Re: 1292: Pi vs. Tau

π wins 399533 times; τ wins 400213 times; 200254 ties Good, good... Now let us reject our arbitrary choice of taking decimal digits modulo 5 and using a specific RPS-configuration... unless τ wins using the quinary expansion and a specific RPS-configuration. I think one of the few 'fair' ways (inst...

- Sun Nov 24, 2013 9:57 am UTC
- Forum: Mathematics
- Topic: Base Prime
- Replies:
**3** - Views:
**1907**

### Re: Base Prime

Can you think of advantages and disadvantages of this system? The biggest disadvantage IMO would be that position k requires p k+1 symbols to be able to represent all numbers, so the elements in your 'array' (a.k.a. positional notation) needs to be of arbitrary size. Oh and at first glance it looks...

- Sat Nov 23, 2013 12:31 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1292: Pi vs. Tau
- Replies:
**124** - Views:
**30036**

### Re: 1292: Pi vs. Tau

Wnderer wrote:So is there a winner?

There shouldn't be, as pi and tau are believed to be normal numbers so their wins should even out.

- Fri Nov 22, 2013 12:09 am UTC
- Forum: Site/Forum issues
- Topic: Forum is very very very slow
- Replies:
**69** - Views:
**36636**

### Re: Forum is very very very slow

The bots have receded for the moment it seems. I'll report back when I learn something. I'm all ears. :) That pool is currently overloaded by spam bots*, though I've sort of dropped a large chunk of China's IP space already*. Don't the spambots always annoy the pool or was/is this a large scale atta...

- Thu Nov 21, 2013 4:51 pm UTC
- Forum: Site/Forum issues
- Topic: Forum is very very very slow
- Replies:
**69** - Views:
**36636**

### Re: Forum is very very very slow

After a database crash the forum is running at full speed for me now.

Why does the damn attachment system reject .htm and even .txt files? I just wanted to add the crash report I got about 10 minutes ago: http://updo.nl/file/97b867e7.htm

Why does the damn attachment system reject .htm and even .txt files? I just wanted to add the crash report I got about 10 minutes ago: http://updo.nl/file/97b867e7.htm

- Wed Nov 20, 2013 1:55 pm UTC
- Forum: Site/Forum issues
- Topic: Forum is very very very slow
- Replies:
**69** - Views:
**36636**

### Re: Forum is very very very slow

Is there a dev/admin who'd like to speak up and acknowledge the problem, say the cause is known and the solution is underway and the site will be back to normal tomorrow? :D (I like such devs, especially if the problem is solved within the expected time) Oh and if Time's the cause, just delete all t...

- Mon Nov 18, 2013 1:36 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1292: Pi vs. Tau
- Replies:
**124** - Views:
**30036**

### Re: 1292: Pi vs. Tau

The compromise should be the Chinese symbol for Rooster: 酉. I instantly agree, for it is a rooster. :D https://lh4.googleusercontent.com/-CsoSwfT17TI/UonLj7RSFmI/AAAAAAAA3YI/pLfUo-boH60/w512-h347-no/angle+table.png Am I being nerd-sniped here? (looking at the last two columns)

- Sat Nov 16, 2013 11:04 pm UTC
- Forum: Mathematics
- Topic: Not sure
- Replies:
**18** - Views:
**2881**

### Re: Not sure

Obviously this is a perspective projection rather than a parallel projection. Well yeah, I was confused about that because the other projections were seemed were seemed parallel - is it possible to have a projection like David gave? (true, it's a second order projection, so you could combine a para...

- Sat Nov 16, 2013 1:15 am UTC
- Forum: Mathematics
- Topic: Not sure
- Replies:
**18** - Views:
**2881**

### Re: Not sure

davidstarlingm wrote:which is extended at right angles:

I still don't get this one. When using an

- Fri Nov 15, 2013 4:17 pm UTC
- Forum: Mathematics
- Topic: Not sure
- Replies:
**18** - Views:
**2881**

### Re: Not sure

Aaaaaannnd I'm lost. I would love to hear an explanation for that if you've got the patience (But your time might be better spent elsewhere!) Thanks again! You could visualise it as a 'ghost cube' next to (or partly overlapping) your original cube of 8 blocks. (in maths it's called a hypercube tess...

- Fri Nov 15, 2013 2:34 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1288: "Substitutions"
- Replies:
**147** - Views:
**39781**

### Re: 1288: "Substitutions"

I do find it hilarious that this thread has gone three pages without anyone noticing that the replacements are already happening on this forum... i find it hilarious that someone can post a statement like this wihout[sic] first checking its veracity. like, by reading three posts up. I find you all ...

- Fri Nov 15, 2013 11:16 am UTC
- Forum: Mathematics
- Topic: How many digits of Pi do you know?
- Replies:
**445** - Views:
**102297**

### Re: How many digits of Pi do you know?

3.14159265

I sometimes add another 1/20th of the result so you get another digit of precision. (assuming decimal)

Xenomortis wrote:But to be honest, in situations where I don't have a calculating machine, π = 3.

I sometimes add another 1/20th of the result so you get another digit of precision. (assuming decimal)

- Fri Nov 15, 2013 9:58 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1291: "Shoot for the Moon"
- Replies:
**67** - Views:
**15559**

### Re: 1291: "Shoot for the Moon"

da Doctah wrote:Depends on your vector. You could escape the Earth/Moon system but reduce your relative velocity around the Sun in such a way that your orbit will decay and you'll fall in.

Exactly; shoot for the moon during first quarter moon and you'll either reach it or become a sun god.

- Sat Nov 09, 2013 4:34 pm UTC
- Forum: Mathematics
- Topic: Uniform Probability Distribution Over All Natural Numbers
- Replies:
**13** - Views:
**4783**

### Re: Uniform Probability Distribution Over All Natural Number

This discussion does bring up the question of how to treat an unknown distribution. For example, in one of those logic puzzles where the antagonist writes a natural number down and puts it in an envelope, you have no information about the method by which the number was selected. As such, you genera...

- Sat Nov 09, 2013 1:31 am UTC
- Forum: Mathematics
- Topic: Uniform Probability Distribution Over All Natural Numbers
- Replies:
**13** - Views:
**4783**

### Re: Uniform Probability Distribution Over All Natural Number

Can't you state the probability of one value (or a finite range in an infinite space) as a limit, P(x=n)=lim

Without 'solving' the limit, I'd say the whole thing sums to 1. The iffy part here is that lim

_{t->0+}t ?Without 'solving' the limit, I'd say the whole thing sums to 1. The iffy part here is that lim

_{t->0+}t is equal to 0 (at least in most definitions).- Wed Nov 06, 2013 11:16 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1286: "Encryptic"
- Replies:
**102** - Views:
**31129**

### Re: 1286: "Encryptic"

I couldn't withhold myself from checking out the database - the excerpt on xkcd is indeed made up.

Thanks, now we have to reverse-crack your username...

mishka wrote:Okay, since it's out now, my password for adobe is crayola.

No, I didn't use it elsewhere.

No, I didn't even use the same username as on xkcd.

Thanks, now we have to reverse-crack your username...

- Sun Nov 03, 2013 1:57 pm UTC
- Forum: Mathematics
- Topic: Permutations and Combinations
- Replies:
**7** - Views:
**2122**

### Re: Permutations and Combinations

To add to that: in general, if two choices are independent, you get the total number of possibilities by multiplying those of the individual choices.

- Thu Oct 24, 2013 10:10 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1281: "Minifigs"
- Replies:
**105** - Views:
**19400**

### Re: 1281: "Minifigs"

The UK's Daily Mail, a god-awful excuse for a paper filled with vitriol and spite, whose online incarnation regularly runs articles pretty much to troll the internet into providing pageviews, has run this comic as a news story, complete with their own uglier (and copyrighted to themselves) version ...

- Mon Oct 21, 2013 10:37 pm UTC
- Forum: Mathematics
- Topic: Optimization Woes with Pizza
- Replies:
**22** - Views:
**4939**

### Re: Optimization Woes with Pizza

I'm curious as to how you could run a simulation to approximate solutions to this problem. Surely one could do better than applying plenty of random slices and randomly flood-fill the regions until there are n regions of τ/n area, but I can't see how. Maybe nature can help; something like multiple v...

- Sun Oct 20, 2013 5:55 pm UTC
- Forum: Mathematics
- Topic: Optimization Woes with Pizza
- Replies:
**22** - Views:
**4939**

### Re: Optimization Woes with Pizza

Are we allowed to fold the pizza, and does this give us any saving in the total length of cuts? I like your style. :lol: However I think it's supposed to be a 2-dimensional optimisation problem. Supporting Qaanol's idea: circles have the least boundary-to-surface ratio, so shapes that resemble disk...

- Fri Oct 18, 2013 10:13 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1279: "Reverse Identity Theft"
- Replies:
**144** - Views:
**38153**

### Re: 1279: "Reverse Identity Theft"

I always assumed my name was unique, since my last name is only used by a handful of people in a small region in the Netherlands and Germany. (so worldwide I presume it's limited to a hundred or so people) But some time ago I started receiving mail about the weekly work schedules of a restaurant not...

- Thu Oct 17, 2013 3:01 pm UTC
- Forum: Mathematics
- Topic: n sided polygon, n < 3
- Replies:
**35** - Views:
**6225**

### Re: n sided polygon, n < 3

And when n=cheese the sum is 180cheese - 360. Sure, we can all string the relevant symbols together, but that doesn't necessarily imbue them with meaning. On the other hand, most definitions of polygons allow for a digon and some for a monogon. And that formula is said to hold for every polygon in ...

- Wed Oct 16, 2013 9:48 am UTC
- Forum: Mathematics
- Topic: Substitution systems
- Replies:
**6** - Views:
**2483**

### Re: Substitution systems

With only 1 rule, you can only make recursive/repetitive patterns, no matter how large your alphabet is. Try recursive replacing some text in a document of yours. (or perhaps a lorem ipsum) If your search string matches anything, it'll replace it with the replacement string (duh) and it's done. Howe...

- Sun Oct 13, 2013 1:08 am UTC
- Forum: Mathematics
- Topic: I want to compare the random numbers generated from many RNG
- Replies:
**12** - Views:
**3421**

### Re: I want to compare the random numbers generated from many

For an LFSR to have a maximal period (2 n -1) for the number of bits** stored (n), you must find an irreducible polynomial, that is, a polynomial that can't be described as a product of two other polynomials (both having at least degree 1, since you can always multiply by a constant). For example th...

- Fri Oct 11, 2013 4:12 pm UTC
- Forum: Mathematics
- Topic: I want to compare the random numbers generated from many RNG
- Replies:
**12** - Views:
**3421**

### Re: I want to compare the random numbers generated from many

I tried substituting 2 for x and ended up with really bad numbers. Ah, no, that's not how those polynomials work. The Xs are not supposed to be subsituted for a number, but rather represent the state of a bit at a certain position. x 4 +x 3 +1 = 1 *x 4 + 1 *x 3 + 0 *x 2 + 0 *x 1 + 1 *x 0 can be rep...

- Tue Oct 08, 2013 11:48 pm UTC
- Forum: Mathematics
- Topic: Product numeral system
- Replies:
**2** - Views:
**1207**

### Product numeral system

Consider a 'universal' numeral system (for positive integer approximation) using rods and dots. A group of n rods simply denotes a number n, while a dot denotes multiplication of the number on the left with the number on the right. 2 = || 4 = |||| or ||.|| 12 = ||.|||.|| or |||.||.|| or ||||.||| Why...

- Sat Oct 05, 2013 4:21 pm UTC
- Forum: Language/Linguistics
- Topic: "Have" sex?
- Replies:
**18** - Views:
**7302**

### Re: "Have" sex?

Not really, because "have" means "eat" in those cases, same way you can have a sandwich. One does consume a marriage and eating out your partner isn't uncommon either... :roll: One "consummates" a marriage, unless one is a kaiju. I keep learning something every day on ...

- Sat Oct 05, 2013 3:11 pm UTC
- Forum: Language/Linguistics
- Topic: "Have" sex?
- Replies:
**18** - Views:
**7302**

### Re: "Have" sex?

gmalivuk wrote:Not really, because "have" means "eat" in those cases, same way you can have a sandwich.

One does consume a marriage and eating out your partner isn't uncommon either...

- Fri Oct 04, 2013 8:58 pm UTC
- Forum: Language/Linguistics
- Topic: "Have" sex?
- Replies:
**18** - Views:
**7302**

### Re: "Have" sex?

Even still that begs the question "Why do we say 'have sexual intercourse'"? The only phrases I can think of that work this way have an article, like "have a conversation" You have sugar, right? Not 'a sugar'. Intercourse is just an uncountable noun AFAIK. For all I know having ...

- Thu Oct 03, 2013 8:53 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1272: "Shadowfacts"
- Replies:
**101** - Views:
**22244**

### Re: 1272: "Shadowfacts"

Come to think of it, even if a horse is always correct, you can't really describe it as a "correct horse". The word correct has a different meaning when used before the noun. A trainee vet should always make sure (s)he shoots the correct horse. If you want to make clear you're talking abo...

- Wed Oct 02, 2013 8:15 am UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1272: "Shadowfacts"
- Replies:
**101** - Views:
**22244**

### Re: 1272: "Shadowfacts"

After a rough night a comic with simple humour is greatly welcomed.

I see what you did there.I just wanted to quote the joke

rhomboidal wrote:After Mister Ed and ShadowFacts, talking horses aren't quite as magical as I imagined. (Though, apparently, ponies are to some people.)

I see what you did there.I just wanted to quote the joke