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Root 2 - Numberphile

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Numberphile

Numberphile

Күн бұрын

The square root of two is a fascinating number with a long and sordid history. It also forms the basis of most office paper, such as A4, A3, etc.
More links & stuff in full description below ↓↓↓
This video features Professor Roger Bowley and Dr James Grime.
NUMBERPHILE
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Пікірлер: 5 300
@razwanabdullah2745
@razwanabdullah2745 9 жыл бұрын
i took my root beer and put it in a square cup...now its just beer
@vF3ARv1
@vF3ARv1 9 жыл бұрын
Oh, you're funny...
@potenvandebizon
@potenvandebizon 9 жыл бұрын
Wish that would work,
@potenvandebizon
@potenvandebizon 9 жыл бұрын
***** It failed, but when I put a pie in a circular cake pan it fit exactly.
@LordZanba
@LordZanba 9 жыл бұрын
Mistermaarten150 Funny, I managed to fit a pie perfectly in a square cake pan.
@LordZanba
@LordZanba 9 жыл бұрын
naphackDT Wait, hear me out! Pies are squared, I swear!
@DragongodZenos
@DragongodZenos 7 жыл бұрын
why do i do this to myself. late night math videos on youtube when i cant even do basic math
@mecca4521
@mecca4521 7 жыл бұрын
DragongodZenos me too i do that all the time
@199022009
@199022009 7 жыл бұрын
I can do basic math! :D But that's about it. Basic math. :(
@GustavLjungberg
@GustavLjungberg 7 жыл бұрын
+199022009 What counts as basic maths?
@thelittleoctopus2353
@thelittleoctopus2353 7 жыл бұрын
studying calculus made me cry don't put yourself through the torture XD
@199022009
@199022009 7 жыл бұрын
VolvoGustav 10+1=3
@ConsolePit
@ConsolePit 6 жыл бұрын
I can't stop watching these videos. I barely understand anything going on, but I think I've learned what a number is, so I'm pretty excited
@hareecionelson5875
@hareecionelson5875 2 жыл бұрын
It's like dogs watching humans have *** The dog doesn't know what's going on, but the dog is still enjoying it
@sumdumbmick
@sumdumbmick Жыл бұрын
doubtful. I've literally never met anyone over the age of about 6 or 7 who knows what a number is. 7 and -7 are both considered numbers. but... they have the same number component. so that's like saying 7 apples and 7 turnips are numbers. but... only the number component is the number, right? what about 7i? that's an imaginary number, but it shares the same number component as 7, -7, 7 apples and 7 turnips, so it can't be a number either. only the number component is truly a number there, too. ok, how about 7/3 then? surely fractions are numbers, right!? well... no, because we still have 7 of something, just like 7i is 7 instances of i, and 7 apples is 7 apples. turns out almost nothing that's called a number by mathematicians actually is one. even positive 7 is not actually a number, because it has a sign component which opposes the sign of -7, but +7 and -7 share the same number component. turns out all of these things are vectors, not numbers. and this is actually important because mathematics does not operate over numbers at all. it actually doesn't even operate over vectors (which is the pairing of a number and a unit). it operates over units. and this has consequences that will probably completely blow your mind. for instance, we can see that mathematics operates over bare units by noting that unit conversions are possible: - 4 inches * 2.54 cm / inch = 4*2.54cm * inch/inch = 10.16cm * 1; so dividing a bare unit by itself yields the dimensionless multiplicative identity, 1... inch/inch has absolutely no number component at all, so that division was not over numbers, or even vectors, but pure units. but this carries further, because it means that 1+1=2 is actually false: - 1C flour + 1C flour = 2C flour; seems to work here, 1+1=2 is demonstrated, right? - 1C flour + 1 egg = uhm... not 2 of anything; so NOT(1+1=2) is also demonstrated this means that the truth of 1+1=2 is undecidable, which notably contradicts current mathematical dogma because in 1929 Mojzesz Presburger took Peano Arithmetic, removed multiplication from it, and allegedly proved that addition over bare numbers is decidable. it was two years later that Kurt Godel published his Incompleteness Theorems showing that Peano Arithmetic in its original form is undecidable, and this result was what shook up the Hilbert Program and basically threw 20th century mathematics into a minor crisis that remains unresolved. the deep problem here is that Peano Arithmetic and everything related to it, even alternatives to it used to build up to different formulations of the current foundation of mathematics, assume that numbers are the basic object over which mathematical operations work. and this mistake is the source of all the trouble, since math does not operate over numbers mathematicians must go around claiming that vectors are numbers, and since math doesn't operate over numbers but Peano Arithmetic does, the sorts of things which can be proven within a logical framework that accepts Peano's Axioms will be fraught with contradictions, which gives us Godel's Incompleteness Theorems.
@PYSSMILK
@PYSSMILK Жыл бұрын
What is this comment thread XDDD
@swedishpsychopath8795
@swedishpsychopath8795 Жыл бұрын
@@sumdumbmick In Korea they laugh of -7 . They actually laugh of one divided by zero too 1/0 .
@erikd1012
@erikd1012 Жыл бұрын
​@@PYSSMILK Haha thought the same thing
@X-Scorpio-33
@X-Scorpio-33 2 ай бұрын
Terrence Howard anyone?
@willsheridan270
@willsheridan270 8 жыл бұрын
At this point in time, the number of views this video has is 1.414 million (root 2 x 1000000). You have no idea how long I waited for this moment.
@pneuma1387
@pneuma1387 5 жыл бұрын
Will Sheridan now we have to wait for 14 mil views
@adamrowedotcom
@adamrowedotcom 5 жыл бұрын
Root too long?
@adnanfahed8915
@adnanfahed8915 5 жыл бұрын
now its 2.818m (root 2*2*1000000)
@kallek919
@kallek919 5 жыл бұрын
W i l l: I think 1414213 (rounded) is (root 2*1000000000000) or (root 2*10^12).
@GruntDestroyarChannel
@GruntDestroyarChannel 5 жыл бұрын
Now it's almost exactly DOUBLE
@Yizak
@Yizak 9 жыл бұрын
The overwhelming irony is that if you hear the name Pythagorus, you think of his Theorem, which gives rise to irrational numbers - the very thing he hated!
@akuskus
@akuskus 9 жыл бұрын
Yikak4 Nope, I am only thinking about who is Pythagorus.
@Yizak
@Yizak 9 жыл бұрын
akuskus Alright. Well as a maths student that's what comes to mind. I guess if you are more of a history person it's different.
@wewladstbh
@wewladstbh 9 жыл бұрын
You spelt it wrong, Akuskus was joking.
@Yizak
@Yizak 9 жыл бұрын
kerbalspacevideos I caught on :)
@matheusphillipevelozoamara3262
@matheusphillipevelozoamara3262 7 жыл бұрын
Don't take historical citations very seriously! I mean... we can know for a fact what Pythagoras did, but can never be sure of what he really liked.
@AmonAmarthFan609
@AmonAmarthFan609 3 жыл бұрын
I love re-watching ancient primal numberphile videos and thinking about how when these videos were made, they likely had no idea how popular their channel would end up becoming over the next decade
@andrerenault
@andrerenault Жыл бұрын
I love these videos that are essentially 2 or 3 interviews intercut, or in parallel, about the same topic. Maybe they've fallen out of fashion, but I wouldn't mind more topical videos like these with multiple interviews.
@ar_xiv
@ar_xiv Жыл бұрын
They were pretty popular back then too it’s only grown proportionally
@Phobero
@Phobero 8 жыл бұрын
5:44 - guys, guys, Bruno Giordano was a striker for Napoli football team in the eighties. Philosoper guy is Giordano Bruno.
@santoriomaker69
@santoriomaker69 6 жыл бұрын
Yeah, it's a joke
@djhalling
@djhalling 4 жыл бұрын
I thought that Giordano Bruno was the Italian version of Gordon Brown.
@DavidRTribble
@DavidRTribble 3 жыл бұрын
And Bruno was burned at the stake for postulating that there were other intelligent lifeforms on other worlds and for being a pantheist, not for saying that the Universe is infinite.
@FriedEgg101
@FriedEgg101 8 жыл бұрын
2b squared or not 2b squared?
@ffggddss
@ffggddss 8 жыл бұрын
Yes.
@OleKristianElns
@OleKristianElns 7 жыл бұрын
wauw
@gibbyace5077
@gibbyace5077 7 жыл бұрын
FriedEggSandwich that is the question
@LS-Moto
@LS-Moto 7 жыл бұрын
Commander Keen was an awesome game
@XthegreatwhyX
@XthegreatwhyX 7 жыл бұрын
It's hip to be squared.
@BonelessEar
@BonelessEar 8 жыл бұрын
dont urine towards the wind.. solar wind applies too!
@AakashKumar-tn6yh
@AakashKumar-tn6yh 3 жыл бұрын
???
@gnarf250
@gnarf250 3 жыл бұрын
@@cometzfordays2032 thanks for clearing that up
@Po_124
@Po_124 3 жыл бұрын
@Alaa Alessa the wind will blow the urine towards you. Solar wind applies too lol
@fbn7766
@fbn7766 3 жыл бұрын
@@AakashKumar-tn6yh 4:19
@ijemand5672
@ijemand5672 3 жыл бұрын
urinate*
@nashvillain171
@nashvillain171 3 жыл бұрын
*4:51** "...I can't begin to tell you how much they disliked this."* **Proceeds to tell us how much they disliked it.*
@ilikevideos4868
@ilikevideos4868 2 жыл бұрын
XD
@sandorrclegane2307
@sandorrclegane2307 2 жыл бұрын
It's an expression
@thegrassguy2871
@thegrassguy2871 2 жыл бұрын
And now there is no such thing as dislikes on KZfaq.
@puppergump4117
@puppergump4117 2 жыл бұрын
@@thegrassguy2871 Return KZfaq Dislike extension join the revolution
@familiamarquez3219
@familiamarquez3219 Жыл бұрын
​@@sandorrclegane2307 🤓
@endermage77
@endermage77 4 жыл бұрын
Nobody: The bloke who added a radial blur on the thumbnail: *You have entered the comedy area*
@lokeegnell3991
@lokeegnell3991 4 жыл бұрын
Hahaha
@pikachu2860
@pikachu2860 3 жыл бұрын
@@lokeegnell3991 maybe that 'he have achieved.... komedy !!!!' XD
@Henrix1998
@Henrix1998 3 жыл бұрын
@@pikachu2860 weedeater
@vpfan207
@vpfan207 9 жыл бұрын
"The square root of 2 is about 1.41 something or other." Nice.
@chumsky8754
@chumsky8754 7 жыл бұрын
Calculators can't explain why no fraction can be the square root of 2. Most give a rational number as the answer, they just give a close answer.
@cellocoversimprov5660
@cellocoversimprov5660 6 жыл бұрын
Well it is...
@user-ft4pb5vb3e
@user-ft4pb5vb3e 6 жыл бұрын
GhostlyJorg Wouldn't it be splendid when we could infinitely calculate something.
@thecakeredux
@thecakeredux 5 жыл бұрын
Well, we have the tools to do that, just not the time. Trickle algorithms can give you any digits of Pi and other irrational numbers with absolute precision.
@colinjava8447
@colinjava8447 5 жыл бұрын
@@chumsky8754 modern calculators are more advanced. If you do sum(1/n^2) for n=1 to infinity, some will give pi^2/6 They have an internal logic that understands special values.
@wheresmyoldaccount
@wheresmyoldaccount 9 жыл бұрын
99/70 = 1.4142857142857... (99/70)² = 2.000204081632653 99/70 is an excellent approximation of √2
@tobiasrehfeldt7092
@tobiasrehfeldt7092 8 жыл бұрын
+wheresmyoldaccount well if we're talking about approximations its not far off, but it's still infinitely far off from being exact
@jackwalsh8601
@jackwalsh8601 8 жыл бұрын
+Tobias Christensen Very nice wording (not far off but infinitely off) #Irrational
@charles3747
@charles3747 8 жыл бұрын
+wheresmyoldaccount (99/70)^2=9801/4900 = (9800+1)/4900 wait you see that let's zoom in 9999 times. (9800+1)/4900 we can do this (2x+1)/x and do this sqrt(2x+1/x) (2x+1)/x approachs 2 for x=infinity so the main function approachs the square root of 2. try it out today! and also if you want to approximate square roots, use this forumla sqrt((yx+1)/x)
@wheresmyoldaccount
@wheresmyoldaccount 8 жыл бұрын
ah ha! (2x+1)/x approaches 2 for x=infinity, because 2x+1 approaches 2x for x=infinity (simplified) x+1 approaches x for x=infinity
@SteelBlueVision
@SteelBlueVision 8 жыл бұрын
+wheresmyoldaccount Oh yeah, try squaring the result of this ratio: 665857/470832 Possibly enough precision to even fool your calculator into thinking that the square root of 2 is rational!
@lenonel3286
@lenonel3286 3 жыл бұрын
I love how they always talk like they're uncovering some massive government conspiracy
@WAMTAT
@WAMTAT Жыл бұрын
Maths is a conspiracy that the government doesn't want you to learn about.
@davidsotomayor8713
@davidsotomayor8713 3 жыл бұрын
@5:20 I was lucky enough to have an awesome professor for complex numbers, he was my AC circuits professor. Everyone in that class was great with complex numbers which worked out well in other math classes. Other students used to hate it when we had to do complex/imaginary numbers.
@LLHLMHfilms
@LLHLMHfilms 8 жыл бұрын
I think that talking about the square root of 2 is pretty irrational.
@ardenvarley-twyman8352
@ardenvarley-twyman8352 8 жыл бұрын
Ha, punny.
@smitty3624
@smitty3624 8 жыл бұрын
+LLHLMHfilms Yes, let's cast them into the Mediterranean.
@t0piass
@t0piass 8 жыл бұрын
oh hello there brother
@smitty3624
@smitty3624 8 жыл бұрын
Perseihottuma greetings fellow loaf bloke
@TonyStark799
@TonyStark799 8 жыл бұрын
Nice one right there.
@HappyBeezerStudios
@HappyBeezerStudios Жыл бұрын
root 2 is indeed one of my favorite numbers. It comes more up in daily life than I thought.
@mydemon
@mydemon 4 жыл бұрын
A4 "pretty standard in most of the world" *Cries in freedom paper*
@jacobshirley3457
@jacobshirley3457 4 жыл бұрын
So close, so far.
@lenonel3286
@lenonel3286 3 жыл бұрын
US doesn't use A4?
@andreysilva8418
@andreysilva8418 3 жыл бұрын
@@lenonel3286 its uses has A4 paper and their weird paper
@lenonel3286
@lenonel3286 3 жыл бұрын
@@andreysilva8418 i hate this knowledge
@BeauDiddley87
@BeauDiddley87 2 жыл бұрын
@@lenonel3286 they use Letter size paper which is slightly wider and shorter (8.5 * 11 inches)
@ronmcasey
@ronmcasey 4 жыл бұрын
“This is A4 paper, it’s pretty standard in most parts of the world.” 🇺🇸: 😬
@garygrass7044
@garygrass7044 4 жыл бұрын
and the standard isn't root 2 but 297/210, though it's close and root 2 is within standard tolerances
@ytbit
@ytbit 3 жыл бұрын
@@garygrass7044 iirc the standard actually mentions the ratio of √2:1 as a defining property (and then goes on to say that all sizes should be rounded to millimeters after the exact calculation).
@ipedros7
@ipedros7 3 жыл бұрын
@@garygrass7044 approximation clearly since they went to lengths to show the SQR(2) is irrational proofs. As explained the purpose was finding a ratio that wouldn't end up being disproportionate with different a / b and SQRroot (2) was as close as it gets.
@jpdemer5
@jpdemer5 3 жыл бұрын
@@garygrass7044 The standard is √2. To meet that standard, 297/210 mm is officially "close enough" to be labeled A4. If you can dial in your machinery precisely enough, you can depart from 297/210, get closer to the standard, and legally label your product A4. Fun fact: There is a corresponding standard for technical pens, so that you can enlarge or reduce a drawing from one A size to another, and continue to add to it with lines of matching thicknesses.
@jpdemer5
@jpdemer5 3 жыл бұрын
@Sjittaste We have A4 - but for some reason it costs 3x as much as 8.5 x 11.
@KeithDart
@KeithDart 10 жыл бұрын
Cool, I didn't know that about the A series paper. Now I'm a fan of the A series Paper (alas, something we don't use in the USA).
@CraftQueenJr
@CraftQueenJr 6 жыл бұрын
Keith Dart except for card stock and other specialty craft paper.
@albrix5
@albrix5 9 жыл бұрын
I'll never ever pee facing the sun again. Thank you, numberphile.
@tehyonglip9203
@tehyonglip9203 3 жыл бұрын
Hipasus : *proof that √2 is irrational in Pythagoras's own theorem* Pythagoras: I'll ignore that
@jeffreywickens3379
@jeffreywickens3379 2 жыл бұрын
I understand about 10% of these videos, but I still watch them. Dr. Grime is awesome.
@clementlebougre1543
@clementlebougre1543 Жыл бұрын
Dude i am french and my schoool juste send me this video haha
@mdsharfuddinmd5710
@mdsharfuddinmd5710 Жыл бұрын
Thank you sir
@joeward1616
@joeward1616 10 жыл бұрын
Oh my gosh, watching these videos just make my day. Whenever my day isn't going so well or I am in a bad mood, I watch these and I feel better almost instantly. THANK YOU NUMBERPHILE!
@thecsslife
@thecsslife 9 жыл бұрын
The proof was very clearly demonstrated, thank you!
@justaregulartoaster
@justaregulartoaster 4 жыл бұрын
This is how i discovered how useful algebra is. I used my basic knowledge to find out what the ratio between the sides on paper is. From that moment on, i was interested.
@puppergump4117
@puppergump4117 2 жыл бұрын
@@abirdthatflew tbh calculus is the one that's just approximations, algebra gets you answers.
@mdsharfuddinmd5710
@mdsharfuddinmd5710 Жыл бұрын
Thank you sir
@rubenoh07
@rubenoh07 7 жыл бұрын
3:16 "Pssssst... pssssssssssssst* (*whispering*) "Hey kid, wanna learn some maths"?
@jjbudinski8486
@jjbudinski8486 3 жыл бұрын
I love these simple, historical videos about well known mathematical concepts, another favorite is the one about zero.
@idlingdove
@idlingdove 9 жыл бұрын
Brilliant. I always knew there was something special about √2. This argument is based on the fact that the ratio of √2 to 1 becomes the ratio of 1 to √2 when you divide the larger amount (the longer side) by 2. You start with a ratio of √2:1. Divide the larger amount (the longer side) by 2, you get (√2/2):1. But if you multiply (√2/2) by √2 top and bottom, you get (2/2√2), which is equal to (1/√2). So the new ratio becomes (1/√2):1, which is the same as the ratio √2:1. And so on ad infinitum: the ratio of the sides will always be √2:1 when you halve the longer side.
@cookedguppy1933
@cookedguppy1933 7 жыл бұрын
I don't really like math but I like Numberphile for some reason.
@Andrew..J
@Andrew..J 7 жыл бұрын
You a) dont like being forced to learn math, or b) dont like the math youre being taught. Math is sooooo interesting when you sit down and learn and understand it. My first time learning and logarithms and exponents in school i HATED it, later on i looked it up on my own time and was fascinated by it.
@hewwokitty
@hewwokitty 7 жыл бұрын
+Andrew Jatib Interesting- I hated math up until 9th grade when I got a great teacher who made me want to excel at it and love doing it in general. It's my favorite subject and pastime :)
@theywalkinguptoyouand4060
@theywalkinguptoyouand4060 6 жыл бұрын
Well learning and life shouldn't always be fun.
@numbr6
@numbr6 6 жыл бұрын
You really do like math. You didn't like the way math was taught when you were in school. Most math classes do a poor job making math interesting and relevant. Numberphile does both, which is why you like this channel.
@mitchellwodach2215
@mitchellwodach2215 6 жыл бұрын
+Andrew Jatib me too
@andrewjones1143
@andrewjones1143 6 жыл бұрын
My favorite thing about the square root of 2 is that if you multiply it by itself, you get 2 EVERY TIME. Mind blowing!
@freshrockpapa-e7799
@freshrockpapa-e7799 11 ай бұрын
Any square root time itself is the number everytime
@andrewjones1143
@andrewjones1143 11 ай бұрын
@@freshrockpapa-e7799 I made this comment 5 years ago, so I can't be sure, but I'm fairly certain I was being sarcastic when I wrote it.
@SteveMcRae
@SteveMcRae 10 жыл бұрын
PYTHAGORAS101 I am curious to your statement of "SQRT (2) IS RATIONAL". Would you agree on a definition for rational numbers such as ℚ = {m,n} | (m,n) = 1 and m,n ∈ ℤ where n ≠ 0} where the ordered pair (x,y) is equivalent to gcd(x,y). If you accept this definition then what two elements of ℤ would satisfy this definition to place √2 as an element of ℚ? Would you also agree that x^2 = 2 has no solution in ℚ? Allow me to give a more detailed Proof by contradiction from some lecture notes I found: Assume x ∈ ℚ satisfies x^2 =2. if (-x)^2 = x^2 = 2 then x=| x | and x ≥0 therefore x is always positive and x ∈ ℕ. If x= m/n and m,n ∈ ℕ and (m,n) = 1 then since x^2 = 2 then (m/n)^2 = 2 m^2 = 2n^2 making m^2 therefore m^2 is even If m^2 is even it follows that m is even (square of odd number is odd, square of even number is even) if m = 2k with k ∈ ℕ we can substitute 2k for m in m^2 = 2n^2 for m and write it as 2k^2 = n^2 so n^2 is even and therefore n is even. If 2 divides both sides m and n this contradicts the initial condition of (m,n) = 1 Therefore x^2 = 2 has no solution in ℚ. This means that √2 can not be in ℚ and therefore can not be a rational number.
@PYTHAGORAS101
@PYTHAGORAS101 10 жыл бұрын
Steve McRae o.k i'm going to try explain in very simple terms . my calculator says sqrt2=1.414213562,now one may say that number is irrational. Now suppose we adjust the display and we can only see 1.4,nobody can deny that 7/5=1.4 is rational right? another digit 1.41 ,is another fraction 17/12=1.41 plus other decimals also 24/17=1.41 plus other decimals. What is very interesting here is ,both fractions share a number and both are sqrt2 @3digits but one is< sqrt 2 and the other >sqrt 2. Now if you combine both fractions and divide by 2 to get the average you get a convergence which doubles precision to.1.41421,now already we have more than half the digits for sqrt 2 For all 10 digits in the smallest possible terms 338/239 and 239/169 will both result in sqrt2 @5digits and a combined average converges to 1.414213562.(sqrt2 @10 digit) Please see for yourself. This is the realm of the real numbers ,they all exist as eternal converging fractions. The odd/even argument is silly because it assumes it must be one fraction and must be the absolute square root of 2 . Also one could argue that "a" and "b"could never be both even no matter what because of its GCD,so to conclude they are both even is absurd,because fractions are always in their lowest possible terms. This is where the whole argument is futile in the first place .a and b are never, and never, can be both even. any questions?
@SteveMcRae
@SteveMcRae 10 жыл бұрын
PYTHAGORAS101 I'm trying to painstakingly go through your post here, and not trying to ignore anything here...but only can really address some of the larger issues I seem to see here...I will go on the assumption your decimal calculations are correct. It is true that all real numbers can be formed from convergent sequences (Cauchy sequences)...not sure what you mean by all real numbers are formed from converging fractions however. You could as you pointed out try to find any nth place of √2 using what you are saying...but that really has nothing to do with √2 being rational or irrational. In order to claim √2 is rational you MUST be able to give specifically the fraction a/b where a and b are integers that would EXACTLY produce the entire value of √2. What would be a and b that would produce √2? The odd/even argument isn't silly as it is a direct proof by contradiction given the conditions of what it means to be a rational number. Perhaps there is some type of confusion in terminology here. What to you distinguishes between a rational and irrational number?
@SteveMcRae
@SteveMcRae 10 жыл бұрын
PYTHAGORAS101 In regards specifically to the proof that √2 is irrational, I'll simply it a bit and perhaps it may be a bit clearer. a/b = √2 and assume that a/b is GCD(a,b) = 1 so they have no common factors other than 1. Squaring both sides: (a/b) ^ 2 = 2 a^2/b^2 = 2 Rearranging: a^2 =2(b^2) Obviously here a^2 must be even since 2(b^2) will be even as anything times 2 is even correct? (Even numbers are described by {x : x= 2n, n ∈ ℤ}) So a^2 is even, and as such a also much be even since even numbers when squared result in even numbers. So a is EVEN If a is even we can write a=2c This gives us (2c)^2 =2(b^2) 4c^2 = 2(b^2) Diving both sides by two we have: 2c^2= b^2 b^2 now must be EVEN since 2(c^2) is EVEN and therefore b must be even. (Same reasoning as above) So a and b are both even. If they are both even they both can be divided by 2 which directly contradicts the assumption that GCD(a,b) = 1. Where specifically do you see the flaw in this proof? EDIT: "This is where the whole argument is futile in the first place .a and b are never, and never, can be both even." Exactly! Given that the GCD(a,b)=1 then you are right a and b can never both be even...which is why it is a proof by contradiction.
@PYTHAGORAS101
@PYTHAGORAS101 10 жыл бұрын
Steve McRae There is no entire value of sqrt 2 so how can there be a fraction for it ?However there are limitless amounts of fractions that can be constructed for ever real number (sqrt n) for any required decimal precision.(not cauchi ,more fibonacci) In my opinion a number has no status if it labeled irrational ,it is no longer a number because it has no ratio to any other number.Its kind of sad that real number are treated this way.
@SteveMcRae
@SteveMcRae 10 жыл бұрын
PYTHAGORAS101 Why would there be no entire value for √2? Is Pi irrational to you? Even thought that as well can't be expressed a/b where a and b are integers and b is not equal to 0. Your version of mathematics I am sure you are aware dates back to the greeks and even more specifically to Egyptian fraction notation. Are you familiar with that? What you are saying is what they believed. However, we are in modern maths and established modern maths. You do also realize that according to modern maths you would be incorrect would you agree? So you are saying you rather our educational system teach an outdated version of math (Egyptian fraction notation)? Where exactly is the progress there?
@jimmyc3238
@jimmyc3238 10 жыл бұрын
In the US, paper is typically 8.5 inches by 11 inches, a ratio of 1.294... - not quite 1.414... Is office paper different in the UK?
@RapGeneral11
@RapGeneral11 6 жыл бұрын
Well I don't know about urinating against the sun, but I believe i shouldn't urinate against the wind.
@puppergump4117
@puppergump4117 2 жыл бұрын
I tend to not do it outdoors where the neighbors can see me
@Rhovanion85
@Rhovanion85 8 жыл бұрын
Don't urinate towards the son... but whose son?
@Sewblon
@Sewblon 8 жыл бұрын
Don't urinate towards anyone's son. Urinating at other people is crappy behavior.
@orbik_fin
@orbik_fin 8 жыл бұрын
OTOH there are stranger fetishes...
@krisztianszirtes5414
@krisztianszirtes5414 8 жыл бұрын
+orbik Okay, then for you, urinating at other people _without their permission_ is crappy behavior. :D
@ffggddss
@ffggddss 8 жыл бұрын
+Reema Issa Or is that *probloom*, so that it's really *sunflowers* you shouldn't be urinating toward?
@jackiejikariti8718
@jackiejikariti8718 7 жыл бұрын
Your profile picture made that comment.
@splatproductions99
@splatproductions99 9 жыл бұрын
Funny. People hate Maths and yet this channel has over 1,000,000 subscribers.
@overwrite_oversweet
@overwrite_oversweet 9 жыл бұрын
Popo Sandybanks People hate maths the way it's taught in classes. This is better.
@LetsbeYannis
@LetsbeYannis 9 жыл бұрын
Tim Tian Agree!Its being taught by conservative and conformist figures that promote stale thinking!!
@Gomlmon99
@Gomlmon99 9 жыл бұрын
Lots of people love maths...
@StarSkyGamingOne
@StarSkyGamingOne 9 жыл бұрын
Gomlmon99 true dat!
@overwrite_oversweet
@overwrite_oversweet 9 жыл бұрын
StarSky GamingOne Google Translate translates it to "true it!" :).
@Kiwiscore
@Kiwiscore 10 жыл бұрын
"you shouldn't eat fava beans" Now i understand why vihart said pythagoras was afraid of beans
@stephenj9470
@stephenj9470 2 жыл бұрын
That last explanation left me feeling like I was tricked. Like watching a magician make something disappear, or listening to a logician prove something that sounds contradictory...
@BlueL1n3
@BlueL1n3 6 жыл бұрын
the sqrt(2) is also the basis of camera f/stop numbers (1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32)
@buffoonery5021
@buffoonery5021 8 жыл бұрын
I keep cringing really hard when his finger slides by the paper's edge.
@Rhovanion85
@Rhovanion85 8 жыл бұрын
Ahahaha mee too. I was afraid he might cut himself!
@RCmies
@RCmies 7 жыл бұрын
I always cut my fingers when lifting school books from my bag I swear I would have my finger cut off if I done that.
@Kazoeru
@Kazoeru 7 жыл бұрын
Ikr I always thought he would cut himself
@cosmoid
@cosmoid 6 жыл бұрын
Same!
@user-ft4pb5vb3e
@user-ft4pb5vb3e 6 жыл бұрын
Not hard when your fingers are made of dark energy.
@hh8302k
@hh8302k 9 жыл бұрын
Why can't these guys be my Algebra teachers?
@oldcowbb
@oldcowbb 9 жыл бұрын
YoshiFace yes if you go to Cambridge
@theywalkinguptoyouand4060
@theywalkinguptoyouand4060 6 жыл бұрын
YoshiFace you're not smart enough to enter a class with them as teachers. Intelligent people don't blame teachers for their inadequacies.
@FirstNameLastName-tc2ok
@FirstNameLastName-tc2ok 6 жыл бұрын
/r/iamverysmart b/c i passed algebra class
@ilprincipe8094
@ilprincipe8094 5 жыл бұрын
@@theywalkinguptoyouand4060 It seems like you never had a bad teacher havent you?
@adnanfahed8915
@adnanfahed8915 5 жыл бұрын
@@theywalkinguptoyouand4060 i think u are the kind of kid who born with rich family, went to special school and never saw a bad teacher
@tsundereshark5945
@tsundereshark5945 7 жыл бұрын
Had to replay some parts to understand it, but it was worth it, this is amazing!
@JonathanXLindqviust
@JonathanXLindqviust 7 жыл бұрын
This is why basic math needs to be taught to everyone, I read advanced math, I don't remember a fraction of it, but I still have the basics. Understanding this is so godamn beautiful, seeing these patterns. It pains me that not everyone will be able to see these.
@mattshnoop
@mattshnoop 6 жыл бұрын
This is one of the coolest videos I’ve watched in a while!
@Sevish
@Sevish 8 жыл бұрын
The square root of 2, if we think about musical notes, is equal to a tritone. The twelfth root of 2 is equal to a semitone.
@JimCullen
@JimCullen 8 жыл бұрын
+sevishmusic And a tritone was once referred to as "diabolus in musica" (or "the devil in music"), on account of being so dissonant that people thought it must be avoided at all costs.
@Sevish
@Sevish 8 жыл бұрын
+Jim Cullen (Zagorath) It's true, however the old tritones were tuned differently as equal temperament has only been in use for a couple hundred of years. In equal temperament the tritone is equal to the square root of 2.
@JimCullen
@JimCullen 8 жыл бұрын
***** well, not per se. Previous tuning systems were based on natural ratios and frequencies found in the harmonic series. For example, an interval of a fifth was a ratio of 3/2. 12th root 2 is a close approximation of this, but it isn't quite as "perfect" as the natural frequency. What it gives us is a nicer sound in more keys, instead of a perfect sound in one key, and a less nice sound if you're playing out of key.
@Sevish
@Sevish 8 жыл бұрын
+pyropulse Not sure which notes you're talking about, we mentioned a few different classes of intervals already in this thread.
@kevindecara9237
@kevindecara9237 8 жыл бұрын
+sevishmusic Can you explain this some more? how can musical notes be equated to numbers?
@Mameyaro
@Mameyaro 2 жыл бұрын
I love this really weird juxtaposition of "Look at how this math fits really well into itself, as found by Pythagoras." and "Pythagoreans say you shouldn't urinate towards the sun."
@andrewmole745
@andrewmole745 2 жыл бұрын
I really love these videos. One small quibble with Grimes… complex numbers and the mathematics associated with them works well, but that doesn’t mean that complex numbers “exist”. Geometric algebra does a better job of describing the same phenomenon by a different approach (that ends up looking similar, but is based on geometry and vectors instead).
@MuffinsAPlenty
@MuffinsAPlenty 2 жыл бұрын
What does it mean for any mathematical object to "exist"? I'm not sure I understand your distinction here about complex numbers not existing because of geometric algebra.
@andrewmole745
@andrewmole745 2 жыл бұрын
@@MuffinsAPlenty Grimes is the one who said the complex numbers "exist". Geometric Algebra provides a different approach that results in things that act like complex numbers and therefore fulfil the same role.
@JH1010IsAwesome
@JH1010IsAwesome 10 жыл бұрын
My mum thinks that complex numbers don't really exist and were just invented by mathematicians because we couldn't work out the square root of -1.
@ionlymadethistoleavecoment1723
@ionlymadethistoleavecoment1723 7 жыл бұрын
Jack Harrison isn't that a thing of debate, whether numbers exist or we just made them up?
@tarantularose
@tarantularose 6 жыл бұрын
but we did work it out the way we apply our mathematics in anything involving negative square roots is such that it can still end up a real rational positive number at the end of the day, and complex numbers are used in physics and other fields of science plenty, so i can't really see why she'd say it "doesn't exist" when it perfectly validly represents and solves for real world problems
@emilygrootkarzijn6944
@emilygrootkarzijn6944 6 жыл бұрын
I see maths like language sometimes, we as humans made it up, and one could debate whether that makes it 'real' or not, but it is used to work out and communicate processes, and can be applied to the real world
@martinepstein9826
@martinepstein9826 6 жыл бұрын
You can argue that numbers don't exist in general but I don't think any mathematician believes real numbers exist but complex numbers don't. That's because the complex numbers can be constructed from the real numbers using what's called a "field extension". Consider the set of polynomials with real coefficients. Step 1: Define the following equivalence relation: two polynomials a(x) and b(x) are equivalent iff they leave the same remainder when divided by x^2 + 1 - If a(x) and b(x) are equivalent we write a(x) ~ b(x) - The set of all polynomials equivalent to a(x) is called the "equivalence class" of a(x). Step 2: Define the following arithmetic operations: If A and B are equivalence classes then A + B is the equivalence class of a(x) + b(x) where a(x) and b(x) are any polynomials in A and B respectively. - A*B is of course the equivalence class of a(x)*b(x). - If you're thinking this looks a lot like modular arithmetic but with polynomials then you're right, that's exactly what this is. Step 3: Let "i" denote the equivalence class of x and let the real numbers denote their own equivalence classes. And you're done. i^2 = -1 because x^2 ~ -1. Every equivalence class can be written as a + b*i where a and b are real numbers since every equivalence class contains a polynomial of degree 1 or lower. You can now go and do complex arithmetic, derive Euler's formula, or prove the Riemann hypothesis with the comforting knowledge that everything you do is based on a sound theory of purely real numbers.
@rajinfootonchuriquen
@rajinfootonchuriquen 5 жыл бұрын
All abstraction of reallity is made up, and in a deep sense, math works in "real world" because we built it to match with our own abstraction of the world. Math can't exist because our brains simplefy the world around does, so exist but, in our minds and not in nature. And so, if we can agree that negative numbers exist, so they exist. If we can agree that sqrt (-1) exist, so it exist. But always in our minds.
@New_Millennium_Cyanide_Christ
@New_Millennium_Cyanide_Christ 9 жыл бұрын
I'm bad at maths, but I really love your videos and appreciate math science
@aegeanviper73
@aegeanviper73 5 жыл бұрын
I have been looking for this video for some time! I love the way you disprove the idea of only having rational numbers! Math is truly a beauty of nature
@leqaa.B.hamadeh
@leqaa.B.hamadeh 5 жыл бұрын
In the equation at 2:44 pm there is an error that should be placed 0.5 before a squared / squared b
@leqaa.B.hamadeh
@leqaa.B.hamadeh 5 жыл бұрын
@@taigapog if: a=4 , b=2 (2/4 *2 # 4/2)
@leqaa.B.hamadeh
@leqaa.B.hamadeh 5 жыл бұрын
So there is a problem
@leqaa.B.hamadeh
@leqaa.B.hamadeh 5 жыл бұрын
@@taigapog thank you
@supercriticality
@supercriticality 10 жыл бұрын
that guy is asking for a paper cut.
@hubb8049
@hubb8049 5 жыл бұрын
This guy is -crazy- IRRATIONAL!!!
@choiaf.4213
@choiaf.4213 7 жыл бұрын
This is so fascinating! It's weird that a simple number like 2 can have such a complicated square root.
@omikronweapon
@omikronweapon 5 жыл бұрын
In a way, not peeing against the sun makes sense. If the sun's in your eyes, you could be aiming anywhere! Strangely enough, the Pythagoreans also believed "10" was holy and honored it by not meeting in groups larger than ten, but in the painting in the video there's eleven of them (if you don't consider the background to be part of the group)
@levitheentity4000
@levitheentity4000 3 жыл бұрын
1:06 When I was little I didn't know about √2, but I knew that if you folded the paper in half the proportions would be the same
@BrickfilmMan
@BrickfilmMan 8 жыл бұрын
Since √2 is irrational, that means that the ratio of the long edge and the short edge of A4 paper would not actually be √2, since √2 cannot be expressed as a fraction
@MuffinsAPlenty
@MuffinsAPlenty 8 жыл бұрын
Brickfilm Man What you say is true.
@spiderman5z
@spiderman5z 8 жыл бұрын
It can be expressed as a fraction but not as a fraction of 2 whole integers. So the paper must be some decimal/ some other decimal = 2**(1/2) .
@BrickfilmMan
@BrickfilmMan 8 жыл бұрын
Iskander Said The side lengths (both or at least one side) of the paper would have to be irrational in order for the ratio of the long edge and the short edge to be √2, which is an irrational number. Keep in mind that all fractions of _rational_ decimals can be expressed as fractions of integers (ex. 0.125/0.48 = 25/96), and so the side lengths of the paper would have the be irrational for the ratio to be √2. It does not matter if the side lengths of the paper are merely decimals or not, since as I said before, all fractions of _rational_ decimals can be expressed as a fraction of 2 integers. For the sides lengths of the paper to have a ratio of √2, the side lengths of the paper would have to be irrational, and that would be impossible in the real world.
@BrickfilmMan
@BrickfilmMan 8 жыл бұрын
***** Sorry if I have caused any confusion, but what I was trying to say is that the ratio of the long edge and the short edge of A4 paper would not actually be _exactly_ √2, because the values of the long edge or short edge would not be irrational numbers. It is _physically_ impossible to measure irrational numbers; what makes you say that the lengths of the sides would be irrational? Going back to your example, it is not possible to construct a _perfect_ square in reality and you can't slice a square _perfectly_ diagonally. Thus the said √2 value of the diagonal of a square in reality would just be an approximation. Another example would be pi. Pi is an irrational number, and people do not know the _exact_ value of pi. All that humans can see, are rational approximations of irrational numbers. What are irrational numbers? Real numbers that cannot be represented by a ratio of integers. Irrational numbers when written as decimals do not end or repeat. _Physical_ values in real life would not be irrational, and could not satisfy this property, because all measurement is imprecise in the _slightest_ way. I have placed emphasis on the words "physically" and "exactly" to help you understand my message.
@TosiakiS
@TosiakiS 8 жыл бұрын
Brickfilm Man Hmm, I see now. I think what you were trying to talk about were how humans and computers process numbers, which is better described as "measured values" rather than "physical values."
@Aeimos
@Aeimos 9 жыл бұрын
I had to prove √3 is irrational in an exam once. I got it right.
@PM-vs3rh
@PM-vs3rh 6 жыл бұрын
How?
@yuvalnosovitsky1303
@yuvalnosovitsky1303 6 жыл бұрын
Proof by contradiction: Suppose sqrt(3)=a/b where a and b are the smallest possible integers. that means that 3=(a^2)/(b^2) so 3b^2=a^2 now notice that if you factorize a square number, you always get an even number of prime factors: 4=2*2 9=3*3 16=2*2*2*2 25=5*5 and so on so that means that the prime factorization of the right hand side has an even number of factors, and the left hand side has an odd number of prime factors. since both sides are equal, and every number has one and only one prime factorization, we have a contradiction, so our assumption that sqrt(3) is rational is wrong QED BTW, it's pretty easy to generalize this proof to all non-square numbers
@ytterbium4909
@ytterbium4909 5 жыл бұрын
It think this was a joke, a shitty one but still a joke.
@jimbig3997
@jimbig3997 5 жыл бұрын
@@yuvalnosovitsky1303 Very interesting... but in a sense I feel this proof tells me nothing (new). For example the square root of 4 can be represented as a rational number because 4b^2=a^2 for the same reasons. Inside I feel there's something deeper in nature to be seen but this is like restating the same problem.
@zoklev
@zoklev 4 жыл бұрын
@@PM-vs3rh or you could prove it in a way similar to how √2 was proved irrational in this video
@benYaakov
@benYaakov 3 жыл бұрын
At 8:38 , it can be possible , as we can have 0 as an even number too in the fraction .
@SNoCappidona
@SNoCappidona 5 жыл бұрын
@ 8:36 but in physics we can say sqrt2 ≈ 99/70 :) and there is even a way of generating fractions closer and closer to 2 when squared. 41/29 could have also approximated sqrt2. here we can see the formula for generating fractions approximating sqrt2... 41+29=70 and 70+29 = 99. so, you add the numerator and denominator of the last fraction, and then add the two denominators and use it as the numerator for the new fraction. Thus, the next fraction in the sequence would be 99 + 70 = 169
@Olaxan4
@Olaxan4 8 жыл бұрын
I was so afraid he'd get a horrible paper cut when pointing along the edge of that paper.
@dante224real1
@dante224real1 9 жыл бұрын
but a4 paper is a/b=sqr(2)... is a4 paper peeing towards the sun?
@CraftQueenJr
@CraftQueenJr 6 жыл бұрын
Dan -Horsenwelles- Williams I love faulty logic, it makes for some hilarious dinner table conversations.
@subtractorofsouls
@subtractorofsouls 7 жыл бұрын
This was actually really cool. Had no idea that even paper measurements had so much thought behind them (at leeast in Europe). This means that the longer side of A0 is square root of square root of 2 (fourth root of 2)
@Mister_E_or_Mystery
@Mister_E_or_Mystery 3 жыл бұрын
The demonstration at the end was very beautiful, thank you for sharing!
@LePezzy66
@LePezzy66 8 жыл бұрын
Baby, are you √2? Cuz you can't even!
@sciencemkid
@sciencemkid 8 жыл бұрын
lel
@undead890
@undead890 8 жыл бұрын
I was gonna say, "Cause you're so irrational"
@klobiforpresident2254
@klobiforpresident2254 8 жыл бұрын
Baby, are you the square root of negative one? Because you can't be real. There even is a worse one! Baby, are you i? Because you can't be real.
@L4Vo5
@L4Vo5 8 жыл бұрын
What an odd joke
@klobiforpresident2254
@klobiforpresident2254 8 жыл бұрын
L4Vo5 I would say you two are even.
@Viplexify
@Viplexify 10 жыл бұрын
Don't misunderstand 4:46 : not just irrational numbers are such that they "go on forever". 1/3 also goes on forever in its decimal fraction form, although it does so quite predictably.
@SpectatorAlius
@SpectatorAlius 10 жыл бұрын
But they all do it 'predictably': what makes the difference between 'rational' and 'irrational' is that rational numbers always have a decimal fraction expansion that starts repeating and then keeps repeating forever. With irrationals, they are still predictable, but there is no point past which it only repeats.
@Viplexify
@Viplexify 10 жыл бұрын
Sure, I only referred to the vague term "goes on forever"
@SpectatorAlius
@SpectatorAlius 10 жыл бұрын
But "only referring to the vague term" does no good: it must be replaced with something exact.
@Viplexify
@Viplexify 10 жыл бұрын
But " But "only referring to the vague term 'it goes on forever' " does no good: it must be replaced with something exact." does no good: it must be replaced with something exact.
@drkjk
@drkjk 10 жыл бұрын
He meant go on forever without repeating. 1/3 repeats:1.3333...., Pi and sqrt(2) do not repeat.
@EZ2BCHEEZY36
@EZ2BCHEEZY36 5 жыл бұрын
The extent of my post-college education has been your videos, so thanks for that!
@Phymacss
@Phymacss Жыл бұрын
The videos you make now look exactly the same 11 years ago, no wonder why your channel is the best!
@katzuw5995
@katzuw5995 Жыл бұрын
Nice video! It made me love mathematics a lot! thanks for sharing this.
@pfoster1666
@pfoster1666 3 жыл бұрын
When he said A4 is the standard in most countries, I swear I could almost hear a parenthetical United States...
@SraTacoMal
@SraTacoMal 3 жыл бұрын
Me, wearing no jewelry and a carrier for G6PD deficiency: "Tell me more about these Pythagoreans..."
@JanBinnendijk
@JanBinnendijk 4 жыл бұрын
Indeed the ratio of A format Paper is root 2, but, not only the paper size, also the Pen widths for technical drawings have the same ratio, 0.25, 0.35, 0.5, 0.7, 1, and so on.. which means that if a drawing is enlarged, even the line thicknesses remain within the same ratio
@dsinghr
@dsinghr 8 жыл бұрын
mind blown in last few seconds
@svperuzer
@svperuzer 4 жыл бұрын
That proof is incredible. I'm amazed
@shrikesari
@shrikesari 3 жыл бұрын
“A4 paper is pretty much standard throughout the world.” US: We are not the world. Letter and Ledger it is.
@PrivateSi
@PrivateSi 5 жыл бұрын
We did a maths project at school around age 12 called 'maths bracelets'.. I can't remember it properly but we worked out a formula / rule so you could predict whether a division result's decimal looped, recursed or went on forever which was the point of the project. I think we could predict the length of repeating decimals. Wish I could remember the details. I'm not a mathematician. The closest small fractional ratio that fairly accurately approximates root 2 would have been one of the first constants to be used by ancient architects IMO.
@DavidRTribble
@DavidRTribble 3 жыл бұрын
5:11 "We call them irrational numbers because..." They're called "irrational" because they are not "rational", i.e., they're not a "ratio" of integers. The nomenclature has nothing to do with Pythagoras.
@coopergates9680
@coopergates9680 9 жыл бұрын
The ratio of the dimensions of A4 paper is an approximation accurate to five significant decimal digits, not bad.
@AiOinc1
@AiOinc1 8 жыл бұрын
I'd like to see a video on the arc tangent function, and maybe just how far you can calculate the value of Pi, which is four times the arc tangent of one (4*atan(1)). The farthest I can do in my head is 3.1415926535
@AiOinc1
@AiOinc1 8 жыл бұрын
Or maybe you could talk about fractals? My favorite explanation is by theodd1sout: You're a farmer, and you have an infinite amount of fence posts to build an animal pen with, the only catch is that you have to use them all. Technically that should be impossible, but while you were busy theorizing about how impossible it should be, I figured it out for you its this its called a fractal.
@mairiweir14
@mairiweir14 7 жыл бұрын
3.141592653589693238462643383792
@fabian999ification
@fabian999ification 7 жыл бұрын
Assuming if the angle is 1 radian (57.295... degrees)
@StefanVeenstra
@StefanVeenstra 5 жыл бұрын
I work in the printing industry and it is pretty common to round off at certain decimals. A0 = 1 188mm × 840mm A1 = 840mm x 594mm A2 = 594mm × 420mm A3 = 420mm × 297mm A4 = 297mm × 210mm A5 = 210mm × 148mm A6 = 148mm × 105mm A7 = 105mm × 74mm A8 = 74mm × 52mm A9 = 52mm x 37mm You'll notice 148 isn't half of 297 148,50 is. Like wise the short side of an A7 should be 74,25mm It may seem petty, but calculating further on the practice of rounding off these sizes we'd end up with A20 being a square. So while in formula the A-sizes will always be √2, in practice not so much. Though the inner mathematician of me keeps the accuracy to the 2nd decimal after the comma, it is impossible to keep paper in exact ratios when cutting them in half, because it's paper.
@unitedstatesofgreatbritain6238
@unitedstatesofgreatbritain6238 6 жыл бұрын
4:15 well that escalated quickly
@annevanderbijl3510
@annevanderbijl3510 3 жыл бұрын
“the ratio of a4 paper is root 2” boom, root two isn’t irrational!
@kwanryan5914
@kwanryan5914 2 жыл бұрын
James Grime is an AWESOME teacher
@firasnizam
@firasnizam 3 жыл бұрын
very nice information, this is the first time I heard of A4 paper size ratio
@janepianotutorials
@janepianotutorials 10 жыл бұрын
starting with a false assumption, we can prove anything
@batterup98
@batterup98 10 жыл бұрын
If you're referring to the "assumption" that the square root of 2 is irrational, that's the whole idea behind proof by contradiction, which is the method they're using. They assumed the square root of 2 was rational, and from it derived an absurd conclusion. Since this absurd conclusion can't be true, assuming all of their logic after assuming sqrt(2)=a/b is valid, they must've done something wrong, and the only thing left to be wrong is the assumption that the square root of 2 is rational. The general idea is assuming something which you think is false, and derive something absurd, therefore demonstrating you did something wrong along the way. Assuming you made no mistakes, the only thing you could have done wrong was assuming the false thing, so it must be false.
@janepianotutorials
@janepianotutorials 10 жыл бұрын
you're right, getting a contradiction constitutes a proof.
@jakehalford8541
@jakehalford8541 9 жыл бұрын
Jane It does when there are two possibilities
@Crazy_Diamond_75
@Crazy_Diamond_75 9 жыл бұрын
Jane Somebody never took geometry/algebra2 :P
@JacobHuber
@JacobHuber 9 жыл бұрын
You can't prove to me that you exist.
@alanfalleur6550
@alanfalleur6550 8 жыл бұрын
You can generalize this proof to show that the square root of any prime number is irrational if I recall correctly. The strategy is the same. If p is a prime number and p = (a/b)^2, you can look at the prime factorization of a^2 = b^2 x p and show a contradiction.
@mariuszszewczyk3710
@mariuszszewczyk3710 8 жыл бұрын
+Alan Falleur - not only prime
@alanfalleur6550
@alanfalleur6550 8 жыл бұрын
Mariusz Szewczyk How do you generalize it further?
@ianwubby6271
@ianwubby6271 8 жыл бұрын
+Alan Falleur I guess any whole number that's not a square number.
@alanfalleur6550
@alanfalleur6550 8 жыл бұрын
Ian Wubby Of course. That makes sense. If it's not a square number, then you can write it as the product of a whole number and the square root of a prime number, which you know is irrational.
@PersonaRandomNumbers
@PersonaRandomNumbers 8 жыл бұрын
+Alan Falleur Not strictly true. Look at the square root of six. Then it's the product of two square roots of prime numbers, which is not necessarily irrational. I mean, it does happen to be irrational, but you have to generalize the proof further to prove it :P
@wayneosaur
@wayneosaur 2 жыл бұрын
Variation of Brady's proof starting w 2a^2 = b^2.The left side has an odd number of 2's in its prime factorization. The right side has an even number. Replace 2 with any prime number and the proof still works. Thus the square root of any prime number is irrational.
@ankitsingh-tk5jv
@ankitsingh-tk5jv 7 жыл бұрын
Loved the physical interpretation guys
@vitocorleone3764
@vitocorleone3764 8 жыл бұрын
How can the ratio of the paper sides (long side/short side) equal the sqrt of 2 if sqrt 2 cannot be represented by a fraction?
@theKKCD
@theKKCD 8 жыл бұрын
They round it to the nearest milimetre.
@vitocorleone3764
@vitocorleone3764 8 жыл бұрын
KKCD~ [Kush'gr the Impaler] Thats what I figured. Even though it is not exact, I guess it's close enough
@vitocorleone3764
@vitocorleone3764 8 жыл бұрын
MuffinsAPlenty I thank you very much for that response. I absolutely loved how you took the time to explain it (I appreciate KKCD~ [Kush'gr the Impaler] 's comment as well). Is there a channel or blog I can follow you on? You seem very insightful and intelligent. If not, would you be so kind to recommend a website or another form of media that has information akin to what you have written? I do not want a "fun Math Tricks" website, somewhere that goes much more in depth and with more complex topics. Preferably, anything above calculus which I have already mastered. Again, if nothing, then I am satisfied with what you have provided already =)
@vitocorleone3764
@vitocorleone3764 8 жыл бұрын
MuffinsAPlenty Thanks, I'll check them out. I hope to one day be at a your level in mathematics or another area of STEM. I'm in high school right now, and love looking up different areas of math on Wikipedia. However, sometimes I fall into a wikipedia hole from which I cannot escape and must give up my quest for complete understanding. Perhaps one day I will not need wikipedia
@agustinl2302
@agustinl2302 8 жыл бұрын
Am, look, there is no visible comment of "MuffinsAPlenty", and we would like to see the brilliant answer too :D Would you repost it?
@weckar
@weckar 6 жыл бұрын
Here I thought you were going to go for the proof by infinity where you prove that not only a and b are even, but also c, d, and any other number you could put in there down the line has to be even. In other words: You could divide a and b by 2 into infinity but the maths holds that they always remain even, therefore can always be divided again.
@MuffinsAPlenty
@MuffinsAPlenty 6 жыл бұрын
That's probably how the original argument worked! It's a method called "infinite descent", and it's based on the principle that you cannot have an infinitely descending sequence of positive integers. But today, infinite descent proofs are often replaced by "choose a minimal thing and violate minimality" arguments. I guess they feel "cleaner".
@howie5697
@howie5697 6 жыл бұрын
These are really well edited films. Not spliced to make smart people look like idiots, or to make idiots seem smart. Or at least it feels that way. Just information. Well done.
@rich1051414
@rich1051414 6 жыл бұрын
In years past, I am sure I would of been a pythagorean. Early in my life, I discovered the power of ratios, and used them in school in places where they were never intended to derive the correct answers. Obviously, however, that will only take you so far, but I did have an extreme appreciation for them as a child. Luckily, most of my teachers were more impressed with my creative approach to solving problems in the unintended way than they were upset that I didn't apply the concept they intended me to use.
@CraftQueenJr
@CraftQueenJr 6 жыл бұрын
Richard Smith I know, ratios do make instinctual sense.
@swistedfilms
@swistedfilms Жыл бұрын
I had a friend who would constantly use fractions in his answers, much to the frustration of his teachers. "They're more accurate," he would tell them. And he was right.
@HeadCannon19
@HeadCannon19 4 жыл бұрын
The Pythagorean cult’s beliefs were pretty irrational
@JohnCena-kn9tv
@JohnCena-kn9tv 4 жыл бұрын
Hey boo
@husseinnasser
@husseinnasser 10 жыл бұрын
What kind of paper sheet are you using? Where can I get it from
@gideonroos1188
@gideonroos1188 7 жыл бұрын
That proof is juat beautiful. I was partially lost all the way up to the end when you proved b was eve. Had a beautiul eureka moment.
@hugodesrosiers-plaisance3156
@hugodesrosiers-plaisance3156 2 жыл бұрын
And this is the video that finally got me to subscribe to your channel.
@ZiyadAllawi
@ZiyadAllawi 8 жыл бұрын
A0 paper. Its area is exactly 1 m squared. Its dimensions are (2^0.25 × 0.5^0.25) = (1.19 m × 0.84 m). and the ratio between them is ( 2^0.5 )... A4 is one sixteenth of A0, its dimensions are (29.7 cm × 21.0 cm)...
@razhorblahd
@razhorblahd 10 жыл бұрын
Exaskryz It's not arbitrary, a=2c because a is even. That's the definition of an even number. It's a multiple of 2.
7 жыл бұрын
these videos are addictive
@FLUXCAPACITORWIGGLES
@FLUXCAPACITORWIGGLES 4 жыл бұрын
Watching this channel is like self torture. I love the interesting math. I hate the sound the markers make against the paper.
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