0899: "Number Line"

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Brooks Hatlen
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0899: "Number Line"

Postby Brooks Hatlen » Mon May 16, 2011 4:02 am UTC

Image
Alt. Text: The Wikipedia page "Lists of numbers" opens with "This list is incomplete; you can help by expanding it".

He forgot about the realm of imaginary numbers!
Last edited by Brooks Hatlen on Mon May 16, 2011 4:04 am UTC, edited 1 time in total.

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Re: 899: "Number Line"

Postby A_of_s_t » Mon May 16, 2011 4:04 am UTC

I have to say I lol'd at the "largest even prime."
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Re: 899: "Number Line"

Postby Bipod » Mon May 16, 2011 4:06 am UTC

Please tell me I'm not the only one who looked at that Wikipedia page.

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It actually does.

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Re: 899: "Number Line"

Postby Brooks Hatlen » Mon May 16, 2011 4:07 am UTC

It took me the longest to get the President's Day reference. Altogether good comic.

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Re: 899: "Number Line"

Postby Schadenfreude » Mon May 16, 2011 4:07 am UTC

meh. a chart comic of mostly made up stuff about a handful numbers. don't care for it.
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Re: 899: "Number Line"

Postby ferrettt55 » Mon May 16, 2011 4:16 am UTC

Huh, it does start like that. Well, better get started. 1,2,3,4,5,6...

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Re: 899: "Number Line"

Postby drixoman » Mon May 16, 2011 4:16 am UTC

Not educated enough in math to get this sadly...

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Re: 899: "Number Line"

Postby rho421 » Mon May 16, 2011 4:19 am UTC

I feel like I'm really missing something by not understanding why 8 is the largest even prime...

Also, is the 2.9299372 supposed to be implying that pi and e had a kid?

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Re: 899: "Number Line"

Postby Navarr » Mon May 16, 2011 4:20 am UTC

rho421 wrote:I feel like I'm really missing something by not understanding why 8 is the largest even prime...


I must agree. My cohort and I have spent the last 10 minutes or so since reading the comic trying to figure it out.

Still Trying, though.

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Re: 899: "Number Line"

Postby suso » Mon May 16, 2011 4:22 am UTC

You folks talk about the last 22 minutes since the comic was released like it were days.
Imagine theres no signatures....

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Re: 899: "Number Line"

Postby xkcdfan » Mon May 16, 2011 4:30 am UTC

rho421 wrote:I feel like I'm really missing something by not understanding why 8 is the largest even prime...

It's just an absurdist statement meant to make people laugh or be confused. Looks like it worked.

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Re: 899: "Number Line"

Postby A_of_s_t » Mon May 16, 2011 4:33 am UTC

xkcdfan wrote:
rho421 wrote:I feel like I'm really missing something by not understanding why 8 is the largest even prime...

It's just an absurdist statement meant to make people laugh or be confused. Looks like it worked.

That's the reason I laughed. It makes just as much sense as the 0.99 being 0.000000372 less than 1.
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Re: 899: "Number Line"

Postby BlazeOrangeDeer » Mon May 16, 2011 4:34 am UTC

What we have here is some quality parody mixed with math trolling

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Re: 899: "Number Line"

Postby Rajay » Mon May 16, 2011 4:34 am UTC

Is 2.9299372 supposed to be average of e and pi?
Largest even prime number to be 8!!!
You got me there, For a second I was like wait 4X2 is 8 what is going on here.
Overall a good one.

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Re: 899: "Number Line"

Postby grater » Mon May 16, 2011 4:36 am UTC

rho421 wrote:Also, is the 2.9299372 supposed to be implying that pi and e had a kid?


I assumed it was a reference to the whole quantum physics deal of the wave function collapsing if you observe something, but even that's probably taking it way too seriously.

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Re: 899: "Number Line"

Postby duckshirt » Mon May 16, 2011 4:48 am UTC

I feel like there are a lot of references I don't get...
".99... is .000000037" less than 1 - a reference to (single-precision) floating-point numbers?
Either that or I'm just trolled trying to figure out references, in which case, nice work.
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Re: 899: "Number Line"

Postby overslacked » Mon May 16, 2011 4:56 am UTC

duckshirt wrote:I feel like there are a lot of references I don't get...
".99... is .000000037" less than 1 - a reference to (single-precision) floating-point numbers?
Either that or I'm just trolled trying to figure out references, in which case, nice work.


.99(bar) = 1 is, for some, a holy war. If nothing can be between .99(bar) and 1, then surely they must be equal, right? :roll:

The largest even prime one made me segfault.

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Re: 899: "Number Line"

Postby stardf29 » Mon May 16, 2011 5:02 am UTC

The .99(bar) thing was amusing, as was the alt-text. Not much else, aside from one thing...

"If you encounter a number higher than this, you're not doing real math"

Next number: 9

Well, that explains Cirno's Perfect Math Class.

(If you don't get what I'm talking about, please ignore it...)

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Re: 899: "Number Line"

Postby Brooks Hatlen » Mon May 16, 2011 5:02 am UTC

rho421 wrote:...is the 2.9299372 supposed to be implying that pi and e had a kid?

The part that gave it away for me is "observed". It's halfway between e and pi just like President's Day (which most schools and employers observe) is halfway between Lincoln and Washington's birthdays.

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Re: 899: "Number Line"

Postby A_of_s_t » Mon May 16, 2011 5:04 am UTC

Anyone else feel sad that 5 and 6 are unexplored?
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Re: 899: "Number Line"

Postby Siggy313 » Mon May 16, 2011 5:04 am UTC

There is actually an interesting short story about the number between three and four. They call it "bleem" though. Not entirely sure how to post a url here as a link, but here's the story itself.
http://www.strangehorizons.com/2000/20001120/secret_number.shtm

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Re: 899: "Number Line"

Postby Hendecatope » Mon May 16, 2011 5:07 am UTC

I can't supply all the details, but there might be some grounds for 8 being the supposed largest even prime joke.

First, "All primes are odd except 2, and 2 is the oddest of all". It's my understanding that when something in number theory is proven and lots of it depends on looking at things "p-adically" the first paper proves it for all odd primes. Then, a year later someone comes back and does the hard 2 case.

One issue with 2 is it's representatives. Odd prime numbers are balanced in that for 3 we have "-1, 0, 1". Two is special since we either have "-1,0" or "0, 1".

I've never actually had to do this but apparently it's common practice to look at every 2 case as an 8 case. (For one thing, 2 has trivial squares like 0 and 1. Moving to 4 and then 8 adds some flexibility)

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Re: 899: "Number Line"

Postby phlip » Mon May 16, 2011 5:09 am UTC

Brooks Hatlen wrote:The part that gave it away for me is "observed". It's halfway between e and pi just like President's Day (which most schools and employers observe) is halfway between Lincoln and Washington's birthdays.

Ah, that explains a lot, thanks for that.

I assumed it was a Physics joke... like, the theoretical expected values of e and pi are 2.718... and 3.141... respectively, but when actually measuring them in experiments, they're both observed to be 2.9299... instead. Which isn't as funny as that.

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Re: 899: "Number Line"

Postby Cranica » Mon May 16, 2011 5:16 am UTC

Oh dear, Randall has reignited the .9999... = 1 debacle.

Protip: they're exactly equal.

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Re: 899: "Number Line"

Postby xX17GHDUDE17Xx » Mon May 16, 2011 5:23 am UTC

Brooks Hatlen wrote:
rho421 wrote:...is the 2.9299372 supposed to be implying that pi and e had a kid?

The part that gave it away for me is "observed". It's halfway between e and pi just like President's Day (which most schools and employers observe) is halfway between Lincoln and Washington's birthdays.


I didn't know it was halfway, but I still got the President's Day part (Yay me). My reasoning was that President's Day is in February (2) and fairly close to the start of March (.92)... It makes me kind of sad that I don't get the rest of these.
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Re: 899: "Number Line"

Postby phlip » Mon May 16, 2011 5:31 am UTC

duckshirt wrote:".99... is .000000037" less than 1 - a reference to (single-precision) floating-point numbers?

It would be hilarious if he worked that in too, in addition to the 0.999...=1 thing, but it doesn't seem to work... if I'm doing my calculations right, the difference between 1 and (1-ulp) in a float is 2-23, which is 0.0000000119and more digits... which is the right scale (same number of leading zeros) but not the right number, unfortunately. The number 0.000000037 less than 1 isn't an exact float... it's very close (1-3ulp), which would give a value of 0.000000036.

Add in the fact that "37" is the most common random 2-digit number, and I think it was just an invented figure.
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Re: 899: "Number Line"

Postby N1ddhog » Mon May 16, 2011 5:32 am UTC

Okay, from left to right:

Negative numbers: Imitators as in like evil clones from the Mirror Universe or something.

.99: This is .99999999999... on to infinity. It is technically equivalent to one, but is subject to much trolling as it seems like it should be less.

The golden ratio: A pseudoscience/conspiracy theory thing, thus the "Wait come back I have facts". See Wikipedia.

Forbidden Region: Just being silly, I think.

e: Euler's number, a mathematical constant around 2.718 or so(it's irrational). The derivative(and therefore the integral) of ex is itself. It is also the base of the natural logarythm(ln[]) and e(*PI = -1. No joke here. It is, in fact, here:http://xkcd.com/179/

2.9299372: A President's Day joke, I assume. For those of us not from the States, Americans celebrate President's Day on some oddball day between the birthdays of George Washington and Abraham Lincoln.

Gird: I think this is a reference to the Great Rhombidodecahedron, but what it is doing circa 3.5 is beyond me.

Site of the Battle of 4.108: Just being silly, I think.

Unexplored: Map joke, I think. See above.

7: Well, I've never made this correlation but...

8: Not a prime. (2 is the largest/only even prime). Trolling.

If you encounter...: Math nerd troll-bait. Discrete Math rarely deals with things outside of single digits because it is more concerned with methods and abstractions.

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Re: 899: "Number Line"

Postby MikeStern » Mon May 16, 2011 5:37 am UTC

This Comic, argh, must become smarter, learn what it means. It saddens me how little an amount of references I am actually getting(Or is Randall fooling with me and there are no references to get? argh!)

Brooks Hatlen wrote:The part that gave it away for me is "observed". It's halfway between e and pi just like President's Day (which most schools and employers observe) is halfway between Lincoln and Washington's birthdays.


Why must it be a reference to president's day specifically though? Couldn't it just be a reference to any compromise?

I don't know, maybe I don't get it because I'm not in 'Merica.

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Re: 899: "Number Line"

Postby undecim » Mon May 16, 2011 5:45 am UTC

MikeStern wrote:Why must it be a reference to president's day specifically though? Couldn't it just be a reference to any compromise?


"Observed", indicates it's a reference to a holiday, since we "observe" the two birthdays on one holiday in the middle.
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Re: 899: "Number Line"

Postby Flambino » Mon May 16, 2011 5:52 am UTC

xkcdfan wrote:
rho421 wrote:I feel like I'm really missing something by not understanding why 8 is the largest even prime...

It's just an absurdist statement meant to make people laugh or be confused. Looks like it worked.

It's like inverse nerd-sniping, I suppose

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Re: 899: "Number Line"

Postby jareds » Mon May 16, 2011 5:58 am UTC

phlip wrote:
duckshirt wrote:".99... is .000000037" less than 1 - a reference to (single-precision) floating-point numbers?

It would be hilarious if he worked that in too, in addition to the 0.999...=1 thing, but it doesn't seem to work... if I'm doing my calculations right, the difference between 1 and (1-ulp) in a float is 2-23, which is 0.0000000119and more digits... which is the right scale (same number of leading zeros) but not the right number, unfortunately. The number 0.000000037 less than 1 isn't an exact float... it's very close (1-3ulp), which would give a value of 0.000000036.

Add in the fact that "37" is the most common random 2-digit number, and I think it was just an invented figure.

First, 2-23 is approximately 1.19*10-7, or 0.000000119, not 0.0000000119.
Second, although 2-23 is the ulp in single-precision 1.0, the greatest single-precision number less than 1 is 1-2-24, because the ulp changes as you go below an exact power of two. That is, you have 24 bits of precision, so you have 1.111...111*2-1, with 23 ones after the binary point. Ultimately, 1-0.0000000372 does round to the greatest single-precision number less than 1, but I still doubt that was the intent, as it's closer to 1-0.0000000596.

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Re: 899: "Number Line"

Postby Pfhorrest » Mon May 16, 2011 6:02 am UTC

Cranica wrote:Oh dear, Randall has reignited the .9999... = 1 debacle.

Protip: they're exactly equal.

I find the easier way of making this obvious to people is to rephrase the question:

Is 0.000...[infinitely-many-zeroes]...0001 = 0?

People tend to buy that it is more intuitively than that 0.99... = 1: every time you add another zero before that last 1, you get a smaller (in absolute value) number, so infinitely many zeroes gives you an infinitely small (in absolute value) number, i.e. zero. Then you show that 0.00...001 is the difference between 0.99... and 1 (which people also accept pretty easily), and voila, 1 - 0.99... = 0, therefore 1 = 0.99...
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Re: 899: "Number Line"

Postby phlip » Mon May 16, 2011 6:06 am UTC

jareds wrote:First, 2-23 is approximately 1.19*10-7, or 0.000000119, not 0.0000000119.
Second, although 2-23 is the ulp in single-precision 1.0, the greatest single-precision number less than 1 is 1-2-24, because the ulp changes as you go below an exact power of two. That is, you have 24 bits of precision, so you have 1.111...111*2-1, with 23 ones after the binary point. Ultimately, 1-0.0000000372 does round to the greatest single-precision number less than 1, but I still doubt that was the intent, as it's closer to 1-0.0000000596.

... Dammit. I are good at the counting!

Looking at my notes, it looks like I forgot to shift it up a space... so I was writing "0.111...1" with 23 ones, instead of "1.111...1 * 2-1". I remembered that the digit before the dot didn't count, but I somehow blanked on the fact it had to be a '1'. And having one too many 0's was a similar counting failure.

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Re: 899: "Number Line"

Postby Gammew » Mon May 16, 2011 6:08 am UTC

Noooooooooooooooooo!!! Not the 0.99...=1 debate!

Isn't that the most banned discussion ever on this forum?

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Re: 899: "Number Line"

Postby mjc0961 » Mon May 16, 2011 6:23 am UTC

Haha yes. I don't get much of the other stuff, but I love the "0.99 (actually 0.0000000372 less than 1)*" bit. People will spend so much time arguing about that. In fact, I'd be willing to bet that it's what the guy from this comic is arguing about. :mrgreen:

*Quote not to scale with the bars over the 9's and possibly the # of zero's.

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Re: 899: "Number Line"

Postby Brian-M » Mon May 16, 2011 6:36 am UTC

rho421 wrote:I feel like I'm really missing something by not understanding why 8 is the largest even prime...

You're joking, right? The largest even prime is 2. Any even number higher than 2 is divisible by two, and therefore not prime.

Cranica wrote:Oh dear, Randall has reignited the .9999... = 1 debacle.

I like to think of 0.9999.... as being equal to 1-(1/∞). The real debate should be over whether 1/∞=0 or 1/∞→0.

That one about 7 reminded me about the urban myth of chewing-gum being stuck in the digestive system for 7 years.

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Re: 899: "Number Line"

Postby xkcdfan » Mon May 16, 2011 6:49 am UTC

Brian-M wrote:I like to think of 0.9999.... as being equal to 1-(1/∞). The real debate should be over whether 1/∞=0 or 1/∞→0.

Care to explain how a single number without any variables involved can approach anything?

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Re: 899: "Number Line"

Postby NotAllThere » Mon May 16, 2011 6:56 am UTC

"The largest number is about 45,000,000,000,000 (45 billion) although mathematicians suspect that there may be even larger numbers"
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Re: 899: "Number Line"

Postby skeptical scientist » Mon May 16, 2011 6:57 am UTC

Anyone get the "gird" thing?
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Re: 899: "Number Line"

Postby exhnozoaa » Mon May 16, 2011 7:00 am UTC

N1ddhog wrote:Gird: I think this is a reference to the Great Rhombidodecahedron, but what it is doing circa 3.5 is beyond me.


Eh... I don't see any relation to the Great Rhombidodecahedron. Also, it's not at 3.5; it's an entirely new number between 3 and 4 (I suppose we're now working in base 11... but that would secretly be base 10 because 10 would still count the new digit...).

It reminds me of an episode of iCarly... She was tutoring this boy and told him there was a new number, derf, between 5 and 6. http://icarly.wikia.com/wiki/Derf

Edit: I just noticed that there is some resemblance between the digits for derf and gird. See the above link for a picture of derf. While I wouldn't assume Randall watches iCarly... They do sound similar too.
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