Epic Circles - Numberphile

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  • Опубликовано: 21 сен 2024
  • The man who loved circles (Objectivity): • The Man Who Loved Circ...
    More links & stuff in full description below ↓↓↓
    Pappus chains, circle inversion and a whole lot more in this EPIC video with Simon Pampena.
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Комментарии • 4,6 тыс.

  • @badwulff
    @badwulff 5 лет назад +2254

    Find yourself someone who looks at you the way this guy looks at circles.
    This is true love. It's beautiful.

    • @fyradur
      @fyradur 4 года назад +31

      Ain't nobody who touches you tangently like him

    • @koendos3
      @koendos3 4 года назад +18

      Both thing have 1 thing in common, they kiss

    • @baras9700
      @baras9700 4 года назад +1

      boi, u haven’t watched his question 6 video have u😂

    • @OrBIT_learn
      @OrBIT_learn 3 года назад +4

      @@baras9700 I have. He said he literally cried after solving that question because he was too happy.

    • @joshdoyle182
      @joshdoyle182 3 года назад +6

      I keep looking at girls like that, and they freak out.

  • @zymosan99
    @zymosan99 5 лет назад +1834

    this is a 26 minute video of a man trying to find the relative radius of a circle, and he is very happy too.

    • @YtseFrobozz
      @YtseFrobozz 5 лет назад +79

      It's a long way to go just to get the radius of a circle, but it's kinda worth it for the look of pure, distilled insanity at 21:50.

    • @TakaExc
      @TakaExc 5 лет назад +56

      He's like the Bob Ross of mathematics

    • @patxmcq
      @patxmcq 5 лет назад +5

      @@YtseFrobozz 😂😂😂

    • @tomwallen7271
      @tomwallen7271 5 лет назад +32

      The one thing I got from this video is that there are many many circles, and this guy is having a great time.

    • @mehmetcy84
      @mehmetcy84 4 года назад +2

      Ytse Frobozz 🤣🤣🤣🤣

  • @pablomarcelmx
    @pablomarcelmx 4 года назад +431

    “If you kiss in real life you have to kiss in the inversion too. Exactly”

    • @wknw1442
      @wknw1442 3 года назад +21

      i feel bad for my inversion now

    • @nrm224
      @nrm224 3 года назад +7

      @@wknw1442
      i pulled a few muscles trying to kiss my inversion IRL.

    • @PC_Simo
      @PC_Simo Год назад +2

      @@nrm224 I presume that was before you figured out you just go right up to the circle of inversion, and kiss the perimeter.

    • @davidgould9431
      @davidgould9431 Год назад +2

      "Kiss" is a terrible way to describe two lines being tangent to each other.
      In real life, kissing still keeps the two people or things separate: just very close together. Tangents actually share a point, so the kissing point is necessarily the same in both the real and inverted world.
      I've watched this video a few times and this question always bugged me.

    • @BEDLAMITE-5280ft.
      @BEDLAMITE-5280ft. 29 дней назад

      What does circle inversion have to do with an eclipse?

  • @DarkPhaaze
    @DarkPhaaze 5 лет назад +1281

    You should really ask for consent before touching tangentially.

  • @2Luke100
    @2Luke100 4 года назад +419

    8:35 "Gee you've got good instincts" is my favorite part of the video, the dynamic between these two is hilarious

    • @conkrcstf6405
      @conkrcstf6405 3 года назад +22

      Im thinking Simon originally thought I'd be an oval

    • @snowjix
      @snowjix 2 месяца назад

      @@conkrcstf6405 are you?

  • @washinours
    @washinours 7 лет назад +2707

    Funny to note that 1/95th is also the portion of this demonstration I've understood.

    • @-42-47
      @-42-47 5 лет назад +99

      It is also 1/95th as efficient as just measuring the tiny circle. Though a video where they just do that would only be about 1/95th as interesting to watch.

    • @coolgarrett17
      @coolgarrett17 5 лет назад +101

      @@-42-47 Measuring the tiny circle isn't efficient because error gets amplified at small distances

    • @alexalt2630
      @alexalt2630 5 лет назад +4

      Haha yes. I wish he was clearer

    • @gjermundification
      @gjermundification 5 лет назад +2

      @@alexalt2630 Which part needs to be clearer?

    • @gjermundification
      @gjermundification 5 лет назад +5

      @@alexalt2630 What he shows should make you able to do unlimited iterations of this if you have enough paper; or pixels.

  • @charlesparadise8752
    @charlesparadise8752 8 лет назад +1668

    I'm glad the whole thing came full circle in the end

    • @error.418
      @error.418 8 лет назад +20

      +charles paradise *groan*

    • @fluffycritter
      @fluffycritter 8 лет назад +12

      +charles paradise I see what you did there

    • @sabitalam5277
      @sabitalam5277 8 лет назад +22

      +fluffy I'm an app developer and I'm absolutely *APP*-auled by your statement - I'm afraid I'm going to give you a *PUN*-ishment.
      *bad trombone sounds*

    • @aceman0000099
      @aceman0000099 8 лет назад +13

      *dies from pun

    • @NickiRusin
      @NickiRusin 8 лет назад +39

      +charles paradise It's a shame this video doesn't circulate online more. It deserves a round of applause.

  • @Chausies7
    @Chausies7 5 лет назад +541

    For anyone wondering, the general formula for the area of the nth blue circle (and the nth number in the sequence) will be 1/(15+4*n*(n-1))

    • @maulwurf9414
      @maulwurf9414 5 лет назад +61

      Chausies thanks I might need this eventually

    • @ayaipeeoiiu8151
      @ayaipeeoiiu8151 5 лет назад +70

      Fluffy Boi pretty simple it turns out that you have to add 8*n at the denominator each time

    • @g.tucker8682
      @g.tucker8682 4 года назад +19

      Finally, some actual information! Thanks.

    • @matthewcare9731
      @matthewcare9731 4 года назад +25

      sat thru the entire thing, even tho it is absolutely beyond me. however, despite not understanding the circles per say, the pattern jumped out within seconds, but i could only think of it iteratively. well done finding the general. i wish he had related the geometry to that closed form explicitly. anyway, learning about the inversions was cool.

    • @asarnatskiy
      @asarnatskiy 4 года назад +22

      @@ayaipeeoiiu8151 exactly my thought indeed. I was satisfying hearing the 1/95 at the end, because it was a predictable sequence from the beginning.

  • @WilliametcCook
    @WilliametcCook 5 лет назад +645

    Just imagine trying to solve the initial problem, and you think,
    "quadratic mirrors"
    and it works

    • @jobliar937
      @jobliar937 5 лет назад +16

      think it is a series look for a common difference in the denominators. I mean you can even write the equation for f(n) of it

    • @ahmeduygun7320
      @ahmeduygun7320 4 года назад +2

      @@jobliar937 it must be a series since as you see towards the end what changes for each of those small little blue circles is just one addition of purple circle that is between two parallel lines

    • @PercyPortland
      @PercyPortland 4 года назад +2

      Ahmed Uygun Still trying time figure out how to describe the formula, but am I off in thinking the next in the series should be 1/135?

    • @jimvj5897
      @jimvj5897 4 года назад +8

      @@PercyPortland You are correct. As others have pointed out, the general formula for 1/radius of nth circle is: (2n+1)^2 + 14
      where the first blue circle has n=0.

    • @russellfautheree4650
      @russellfautheree4650 4 года назад +5

      @@jimvj5897 I know it might not be prettier to everyone in an "a*n^2+bn+c" form, but I did it anyway. 4n^2+4n+15. I hope. Been a long time since I touched algebra. I like it in a form that hides the magic.

  • @pumpjackmcgee4267
    @pumpjackmcgee4267 8 лет назад +1102

    This video has instilled me with the very bizarre experience of knowing exactly what you are doing whilst also having no bloody clue what the fuck you are doing.

    • @robertvermillion6816
      @robertvermillion6816 8 лет назад +25

      I know it's called "circle inversion" but I too do not have the foggiest idea what circle inversion actually does.

    • @justclosing
      @justclosing 8 лет назад +3

      When it's finished..what do you do with it?

    • @shaideshe4150
      @shaideshe4150 8 лет назад +24

      Imagine you're inside a circular mirror and you draw a shape on the floor, the inversion of this shape through the circle is how you'd see it in the mirror

    • @TebiByyte
      @TebiByyte 7 лет назад +7

      Welcome to the world of math!

    • @wansichen3743
      @wansichen3743 7 лет назад +8

      try searching for something called hypobolic geometry,hopefully it helps

  • @denelson83
    @denelson83 10 лет назад +265

    It's just adding an arithmetic sequence.
    15 + 8 = 23.
    23 + 16 = 39.
    39 + 24 = 63.
    63 + 32 = 95.

    • @gregor849
      @gregor849 6 лет назад

      Same idea...

    • @adb012
      @adb012 6 лет назад +4

      Here you have another one
      15
      23
      15+23+1=39
      23+39+1=63
      39+63+1=103. Ooooopsy.

    • @howardg2010
      @howardg2010 4 года назад +8

      Me 32 seconds in: "1/95"
      26'35" pass
      Me: "Yup."

  • @simonkulcsar8156
    @simonkulcsar8156 5 лет назад +270

    11:59 He said 'Circle inversion!' with the same level of happiness how Hulk said 'Time travel!'.

    • @sicapanjesis3987
      @sicapanjesis3987 3 года назад +9

      I see this as a absolute win

    • @TeganCantEven
      @TeganCantEven Год назад +1

      Omg. And not only with the same enthusiasm but practically the same cadence!

    • @BMLBiz
      @BMLBiz Год назад +2

      ​​@@TeganCantEven and body language... well it was similar

  • @Spudcore
    @Spudcore 8 лет назад +654

    I can't pretend that I understand it, but I do so much enjoy this guy's enthusiasm!
    He is absolutely loving it!

    • @xavierpaquin
      @xavierpaquin 7 лет назад +19

      Phew!!! This is epic!

    • @Beremor
      @Beremor 7 лет назад +21

      I was thinking the exact same thing! In honor of his enthusiasm, I might actually really try and really understand what's going on. :)

    • @MGmirkin
      @MGmirkin 6 лет назад +2

      Frankly, he's doing that which is the sole function of GOVERNMENT... Taking something **SIMPLE** and **needlessly complicating it** ... ;) (Yes, that's a reference to Burt Gummer from Tremors...)

    • @joshuajames78
      @joshuajames78 6 лет назад +2

      Yes, Adam! I agree!

  • @tggt00
    @tggt00 10 лет назад +352

    this guy scares me, he's eroticly in love with maths.

    • @FairyNuffMuffin2
      @FairyNuffMuffin2 4 года назад +34

      You might say he's a numberphile

    • @amineabdz
      @amineabdz 4 года назад +7

      @@FairyNuffMuffin2 badum tssss

  • @elibusz
    @elibusz 9 лет назад +316

    Beautifully explained. I was excited as a child when the purple cirlcles began to align! hehe.

    • @numberphile
      @numberphile  9 лет назад +64

      Francisco Ibarrola glad you enjoyed it

    • @user-qq6si7zv3t
      @user-qq6si7zv3t 8 лет назад

      +Francisco Ibarrola Purple crayon much

    • @CTJ2619
      @CTJ2619 8 лет назад

      +Numberphile awesome video guys. brilliant

    • @842Mono
      @842Mono 7 лет назад +1

      I wish I could watch that when I was younger really!

    • @e1woqf
      @e1woqf 7 лет назад +1

      me too!!

  • @mysticgeekdom1510
    @mysticgeekdom1510 3 года назад +76

    I just love how happy Simon is the entire time, this is a man who truly loves what he does

  • @cwbeas
    @cwbeas 8 лет назад +1595

    Professor: "Show your work"
    Me: "NO."

    • @cooling9953
      @cooling9953 8 лет назад +11

      Standard

    • @ReZort
      @ReZort 8 лет назад +7

      lol, if I had this problem, then i wouldn't do it either

    • @eliasthememelord
      @eliasthememelord 7 лет назад +3

      Kitty Forest fires

    • @y0Luda
      @y0Luda 7 лет назад +7

      why though..? that's just disrespectful.. just remember how much effort he puts into teaching you things. that's valuable time...

    • @Fudmottin
      @Fudmottin 6 лет назад +31

      It's my time. I paid for it.

  • @alexanderhoang244
    @alexanderhoang244 7 лет назад +993

    I like the part when he said circle

  • @ElectronicTonic156
    @ElectronicTonic156 10 лет назад +166

    That brown paper should be framed and hung on a wall. Beautiful!

  • @Achill101
    @Achill101 3 года назад +92

    Beautiful construction.
    I suspected the final result from the other denominators: 15, 23, 39, and 63.
    From 15 to 23 is 1*8. From 23 to 39 is 2*8. From 39 to 63 is 3*8. From 63 to 95 is 4*8.
    But it's worthwhile to watch him construct the inverted circles and enjoying it.

    • @matthewziemba7526
      @matthewziemba7526 2 года назад +7

      I did the same thing! It was very satisfying to see that I worked it out correctly! I definitely would need to study it a bit more to understand how the circles all worked though... 😂

    • @Achill101
      @Achill101 2 года назад +4

      @@matthewziemba7526 - thank you for reminding me of that video. I watched it again :-)

    • @B.M.0.
      @B.M.0. 2 года назад +4

      kind of seems like a waste of time really when basic sequence math gives you the result in 5 seconds not 26 minutes. I bet the analytics on this video show no watch time between 3:37 and 26:24

    • @Achill101
      @Achill101 2 года назад +6

      @@B.M.0. - I see the meaning of that video in introducing the Inversion At A Circle and giving an example. While I find the inversion elegant and appealing, there seem to not many examples, unfortunately: Ptolemy's axiom, Pappias circles like here, geometrically constructing circles that touch other circles. I would like to know more examples. But I found the construction here marvelous from 14:00 on. Have other watched it, too? If not, I consider it their loss. Watching videos is often "wasting time", but it can be also very entertaining.
      . . . About basic math giving you the results instead: you would still have to prove it. Also here, some steps are cut short, like the radius of the inverted circles being R/16. Yes, I can prove it myself, but they should have added it to the video, I think.

    • @PC_Simo
      @PC_Simo Год назад +2

      Same here 😅.

  • @littlemikey46
    @littlemikey46 9 лет назад +228

    I have no idea what I just watched but now whenever I close my eyes all I see are circles.

  • @jparker588
    @jparker588 10 лет назад +297

    The editing was really nice. I'm sure that explanation took forever in real time. Really cool stuff.

    • @MathHacker42
      @MathHacker42 9 лет назад +1

      The explanation took forever after editing, it's nearly a half an hour long.

    • @Bluemilk92
      @Bluemilk92 9 лет назад +19

      MathHacker42 You'd have to be a rather impatient type of person to consider a half hour as "forever"

    • @RichardHoman9009
      @RichardHoman9009 9 лет назад +1

      Bluemilk92 Maybe in normal circumstances, but this is a RUclips video. They tend to be "long" at just /ten/ minutes. (Mind you, I don't necessarily disagree with you. It's just worth considering.) I, for one, loved this video :)

    • @MathHacker42
      @MathHacker42 9 лет назад +1

      Bluemilk92 Yeah, I may have been a bit hyperbolic, I just meant that it was much longer than a typical youtube video.

    • @Bluemilk92
      @Bluemilk92 9 лет назад +6

      MathHacker42 I guess it just matter what type of content you watch. Since I often watch video-game related videos, I rarely watch anything under 20 minuets

  • @FunkyHonkyCDXX
    @FunkyHonkyCDXX 7 лет назад +201

    I've watched this 4 or 5 times now, and I really feel like I understand it. I use geometry at work constantly (I make custom stairs and handrails, nothing but triangles, circles and the occasional ellipse) and the more I watch this the more I know that this doesn't help me to do with anything with my job, but I love it anyway.

    • @stephenparker7478
      @stephenparker7478 6 лет назад +3

      Perhaps if you were a watchmaker :)

    • @SWIM5QUAD
      @SWIM5QUAD 5 лет назад

      Functional

    • @alexalt2630
      @alexalt2630 5 лет назад +1

      Stephen Parker True point! Didn’t think about how gears are kissing each other in a similar manner

  • @stephenchestnut4844
    @stephenchestnut4844 5 лет назад +117

    "This is epic. This is seriously epic... This is absolutely epic."

  • @tristanhoekstra
    @tristanhoekstra 8 лет назад +797

    Please purchase this guy a compass which you can mount pens and markers in.

    • @outtabubblegum7034
      @outtabubblegum7034 6 лет назад +17

      I recommend a computer.

    • @maxnullifidian
      @maxnullifidian 6 лет назад

      DarkArachnid, that should've been rather obvious, no? LOL

    • @silentgolden8507
      @silentgolden8507 6 лет назад +3

      He didn't use it for a reason could you guess the reason......?

    • @YorranKlees
      @YorranKlees 6 лет назад +1

      Doesn't change the way your brain computes. Besides, you still need a decent algorithm from your brain for the computer to compute.. That is, if you're the one actually giving it a thought. Personaly I would recommend a brain before getting the computer. Which surprisingly gets all back to the original point : where is Numberphile going today ??

    • @clementlefebvre9835
      @clementlefebvre9835 5 лет назад +1

      He actually already has one, he just doesnt use it ^^' :D
      Painful to watch ^^

  • @vondarkmoor1
    @vondarkmoor1 10 лет назад +177

    When you watch and listen to someone like this guy who is SO passionate about something, you cant help but become interested. I love people like this. I wish all the teachers of our children could have this kind of drive.

  • @frankhaugen
    @frankhaugen 10 лет назад +170

    He keep using the word "simple", but this is the inverse of simple

  • @Josh-ti3ox
    @Josh-ti3ox 5 лет назад +72

    I love hearing smart people talk it makes me feel smart

  • @paaaaaaaaq
    @paaaaaaaaq 8 лет назад +89

    This isn't circle inversion. This is circle INVASION.

    • @metoothanks9448
      @metoothanks9448 7 лет назад +2

      nice one

    • @Stillfabulos
      @Stillfabulos 5 лет назад +2

      SO? Now I can find radius of every circle I wish? Even if it'll be the 9999 circle? mhahahahahahah, absolutely power!

  • @akkalat85
    @akkalat85 9 лет назад +117

    @1:24 From now on when I wish to use the word: "kissing" I will substitute the expression "touching tangentially".

    • @mercybellafiore3677
      @mercybellafiore3677 9 лет назад +24

      Yeah, I got to first base last night... I touched Sarah tangentially. No big deal...

    • @EmdrGreg
      @EmdrGreg 9 лет назад +19

      Unfortunately, that would have to exclude touching where anything happens to cross the tangent line--

    • @manioqqqq
      @manioqqqq Год назад

      Bro, i had a dream that i touched my crush tangentally
      (r/outofcontext)

  • @JacobShepley
    @JacobShepley 10 лет назад +204

    1/15, 1/23, 1/39, 1/63, ...
    15, 23, 39, 63, ...
    the difference between each number forms a pattern:
    8, 16, 24
    the next difference would be 32
    63 + 32 = 95
    the next number in the series is 1/95
    the series continues:
    1/95, 1/135, 1/183, 1/239, 1/303, 1/375, 1/455, 1/543, 1/639, 1/743, 1/855, 1/975, 1/1103, 1/1239, 1/1383, 1/1535, 1/1695

    • @danlmd1
      @danlmd1 9 лет назад +1

      The equation to solve for it is
      1/4(4+(n-1(n)))-1
      when n= the place in the sequence you are solving for

    • @JacobShepley
      @JacobShepley 9 лет назад +3

      danlmd1 try 1/( ( 2n+1 )^2+14 )
      n starts at 0

  • @Aquos1432
    @Aquos1432 4 года назад +32

    13:52 *vigorously rubs hands* “This is the reason why I came.”

    • @kakonya2994
      @kakonya2994 4 года назад

      Read this exactly when he says it.

  • @moshe1459
    @moshe1459 8 лет назад +333

    23:40 Pirate does math

  • @Radianx001
    @Radianx001 7 лет назад +204

    New drinking game, everytime he says circle, take a drink

  • @Einken
    @Einken 8 лет назад +641

    Touching tangentially sounds naughty.

    • @Ludix147
      @Ludix147 8 лет назад +25

      or like the name of an indie rock band

    • @sfpt
      @sfpt 8 лет назад +1

      +Kazza FDM genital*

    • @LuukvdHoogen
      @LuukvdHoogen 8 лет назад +1

      It does sound kinkier than kissing, now that you mentioned it.

    • @justclosing
      @justclosing 8 лет назад +1

      You're mixing up tangent with tanga and the string theory

    • @Kebabrulle4869
      @Kebabrulle4869 7 лет назад +5

      what is this comment chain

  • @trequor
    @trequor 5 лет назад +130

    Rewatching this a year later and man there are just too many great lines (both in terms of geometry and dialogue ;)

  • @justinlewtp
    @justinlewtp 9 лет назад +152

    "Yo Dawg, I heard you like circles so I put circles in your circles" :o

    • @liltunwin
      @liltunwin 9 лет назад +5

      +Justin Lew (MC Gamer) That are touching the circles you put in your circles.

    • @hannesjvv
      @hannesjvv 8 лет назад

      +Justin Lew (MC Gamer) Reminds me of XKCD 855. Before all the other "great" minds of the web, Zombo.com's designers used the awesome of circles.

    • @paulinethegreat1
      @paulinethegreat1 8 лет назад +1

      +Justin Lew (MC Gamer) You still don't sound nearly as suggestive as Simon saying the circles are kissing... I will never think of tangents the same way again...

    • @tangobravo5752
      @tangobravo5752 6 лет назад +1

      Ellipse My Ride!

  • @Deathranger999
    @Deathranger999 8 лет назад +88

    For all you commenting about adding 8s repeatedly to the denominator, the most important thing you have to realize is that noticing a pattern does not amount to a proof. The techniques he showed in the video (applied a bit more rigorously, albeit) certainly do. That's the important part. He proved the result, and in quite a marvelous manner.

    • @RYFAMO
      @RYFAMO 8 лет назад +12

      +Kieran Kaempen I might not be a mathematician, but isn't mathematical induction a valid and accepted proof technique? I mean, yes, you could draw a lot of colourful circles for a few hours, but inducing the theory is a lot more practical - especially in real life, when you don't have the time (or even the skills) to elaborate a fancy (and in this case quite unconventional) proof. Nevertheless this was a very interesting approach to the topic and encourages to think out of the box more often.

    • @santoriomaker69
      @santoriomaker69 6 лет назад +5

      I think that Simon (the guy from the vid) shouldn't reveal that many numbers in the pattern, since I can also see a pattern among it (nevertheless, a really beautiful and epic proof). If he did, like say reveal 2 numbers, then the general audience wouldn't be so cocky about it having to SuDdEnLy have the next number.
      Side Note (a REALLY late reply to RYFAMO): The proof Simon presented is a problem WAYYY back when geometry is the algebra of ancient math times.The chain is called the Pappus chain and it was obviously discovered by Pappus of Alexandria on the 3rd AD century. So Pappus actually proved this using the Inversion method, without ANY mathematical induction. So technically speaking, it's a practical proof from ancient times.

    • @semajxocliw
      @semajxocliw 6 лет назад +11

      RYFAMO noticing a pattern and testing it repeatedly is not induction. induction is testing base cases and then showing that because the base cases worked, the next case will also work. Just saying "here's an observed formula for the nth case" doesnt prove anything.

    • @jeffreyblack666
      @jeffreyblack666 6 лет назад +1

      How does it constitute proof?
      He noticed the pattern matches the circles.
      That no more constitutes proof than noticing it matches a formula.
      So his "proof" is no better than simply saying the nth number is 1/(4*n^2-4*n+15).
      All his "proof" actually amounts to is the equivalent of saying 1/(4*n^2-4*n+15) is 1/95 when n=5.
      He has failed to show that this pattern should correspond to the circles rather than simply matches. And that is something that it would be impossible to do as does not fall into the realm of proof.

    • @mapetlv
      @mapetlv 6 лет назад

      The issue here is that the question was introduced in a form of find a pattern question. And then he started drawing circles. So technically all those "adding 8s" are correct answers to the question.

  • @ernestoroybal3682
    @ernestoroybal3682 9 лет назад +1236

    my head just exploded

    • @numberphile
      @numberphile  9 лет назад +126

      Ernesto Roybal ouch

    • @ernestoroybal3682
      @ernestoroybal3682 9 лет назад +59

      I don't recommend it.

    • @lucaspluijgers2975
      @lucaspluijgers2975 9 лет назад +45

      Ernesto Roybal MY HEAD JUST EXPLODED 100 TIMES MORE! why? well you can see 1 on 15, 1 on 23 (plus 8), 1 on 39 (plus 16), 1 on 63 (plus 24) and 1 on 95 (plus 32). so at the start i thought "is it 1 on 95???" at the end "OMG I FRACKING KNEW IT!!!!!!!".

    • @myravied7965
      @myravied7965 9 лет назад +8

      Lucas Pluijgers i had the same, the question is what has that progression with 8*n to do

    • @lucaspluijgers2975
      @lucaspluijgers2975 9 лет назад

      Awesome

  • @danielffnando
    @danielffnando 4 года назад +30

    It's been 4 years since I first watched this video. I was in high school. Numberphile gave me so much passion for mathematics that I'm now in university. Now, 4 years later, I can finally understand this video.

  • @yyGODyy
    @yyGODyy 9 лет назад +126

    I thought it would be 95 because the difference between 15 and 23 is 8, 23 and 39 is16, 39-63=24, so 95

    • @yyGODyy
      @yyGODyy 9 лет назад +10

      yyGODyy Ha i was right. Bitches!

    • @mattmarsh1566
      @mattmarsh1566 9 лет назад +5

      yyGODyy yeah i thought the same thing, lol no need for the 20 minute explanation

    • @shadrack1701
      @shadrack1701 9 лет назад +18

      yyGODyy But what he showed us was the way to prove this using geometry. We could all reasonably assume 95 was the answer (as did I) but using this method it shows the poof of that, very cool.

    • @rasowa2958
      @rasowa2958 9 лет назад +3

      +yyGODyy Yeah, I spotted the same thing (+8+16+24+32).
      Geniuses like us don't need to draw any circles :)

    • @andrewxc1335
      @andrewxc1335 8 лет назад +8

      +yyGODyy Right-o. Now prove it by induction.

  • @tangobravo5752
    @tangobravo5752 6 лет назад +466

    Epic circles but every time Simon says circle it speeds up
    Video only last 2 minutes

  • @RealBenAnderson
    @RealBenAnderson 10 лет назад +392

    What did I just watch.

    • @davecrupel2817
      @davecrupel2817 7 лет назад +13

      something... _sniff_ ...beautiful....

  • @justjack3203
    @justjack3203 3 года назад +33

    Genuinely one of my favourite videos ever on this platform. The pure joy is infectious

  • @Zanpaa
    @Zanpaa 10 лет назад +29

    "We're gonna do this quite rough, Brady, if that's alright."
    Fueling lemons.

  • @Wildpfad
    @Wildpfad 10 лет назад +60

    This guy's enthusiasm is the best =)

  • @PicoriPi
    @PicoriPi 10 лет назад +52

    Brady, this video isn't too long, at least not for me. I have always had a love for circles, so this is right up my alley. It looks like this video could have been two hours long. I would have still watched it multiple times.

  • @MrHeroicDemon
    @MrHeroicDemon 4 года назад +77

    26:29 *Laughs in Mathematician*

  • @ChibiRuah
    @ChibiRuah 10 лет назад +42

    just wow. that structure is truly beautiful. so many amazing properties.

  • @STaSHZILLA420
    @STaSHZILLA420 8 лет назад +136

    From the thumbnail, I thought it was Matthew Santoro with a wig on.

  • @JohnDixon
    @JohnDixon 7 лет назад +184

    To those of you saying that 95 is the obvious answer because it continues the pattern, that is an insufficient answer. There are infinitely many ways to continue this sequence and achieve different numbers for the next term.
    For example, at the start of the video, I noticed that adding the first two denominators gives 15 + 23 = 38, which is 1 less than the next denominator (39). The second pair of denominators added together gives 23 + 39 = 62, which is 1 less than the next denominator (63). By this logic, the next term should have a denominator of 39 + 63 + 1 = 103.
    So using this method, the continuation of the sequence yields 1/103 rather than 1/95.

    • @maxiom7476
      @maxiom7476 5 лет назад +5

      Thank you. My thoughts exactly.

    • @mikebarnes7441
      @mikebarnes7441 5 лет назад

      Its because you did wrong fool

    • @maxiom7476
      @maxiom7476 5 лет назад +27

      @@mikebarnes7441 Either you didn't watch the video, or failed to understand the comment.

    • @mikebarnes7441
      @mikebarnes7441 5 лет назад

      @@maxiom7476 you're wrong

    • @notkamui9749
      @notkamui9749 5 лет назад +31

      @@mikebarnes7441 wow is this the language of gods ?

  • @willmcpherson2
    @willmcpherson2 3 года назад +17

    I love how the spiral of circles inverts to identical circles in a straight line

  • @jacobiusrex6674
    @jacobiusrex6674 7 лет назад +6

    Guys, I'm not kidding when I say this, I did the procedure while watching the video, and it was the most satisfied I have ever been! This is just a wonderful way to show connections between different parts and areas of mathematics. I love these videos, please keep doing the world a favor by making videos like this!

  • @AlanKey86
    @AlanKey86 10 лет назад +160

    I wish I had the programming skill to write some drawing software for this!
    It would allow you to draw a circle of inversion first, then you could draw whatever shapes you liked inside or outside it.
    I'd want to see what happened if I drew squares or triangles... they'd probably come out really weird and distorted.
    **gasp** and then someone would write the 3D version, with a sphere of inversion. And you could pop cubes and pyramids and stuff into it or around it... it would be like a freaky hall of mirrors on acid.

  • @colinprevatt9439
    @colinprevatt9439 10 лет назад +16

    "If two lines touch at infinity...well this is kind of tricky stuff here" My favorite part of the video. :)

  • @GodsBoss
    @GodsBoss 4 года назад +108

    5:58 - "So the radius is 60." -> Every math teacher: "60 what? Apples? Bananas?"

    • @jared8515
      @jared8515 4 года назад

      At first I thought it was mm but I got super confused when it looked more like 3cm and not 6

    • @PaulPower4
      @PaulPower4 4 года назад +25

      I suppose the thing about maths teachers is that they're not just teaching you for maths, they're teaching you for physics, engineering, etc., where having specific units of distance is important. In pure maths, it's enough to say "60 arbitrary units of length" or even just "60".

    • @pranavlimaye
      @pranavlimaye 4 года назад

      @@jared8515 6:24 dude it's clearly 6cm.

    • @andreasschelfhout3472
      @andreasschelfhout3472 3 года назад +1

      @@PaulPower4 In engineering you often find that parameters are "non-dimensionalized" to obtain a general solution, and then you slap on some scaling factors to get the result that fits your needs.

    • @snbeast9545
      @snbeast9545 3 года назад +1

      Not the higher ones. IIRC mine stopped caring beyond Algebra I (or whatever equivalent), unless the problem calls for units (How much thread? or How long of a fence? when your numbers have units).

  • @nabijaczleweli
    @nabijaczleweli 10 лет назад +85

    Brady, You should sell these brown papers at a charity auction or something along those lines.

  • @xMcCarthee
    @xMcCarthee 9 лет назад +91

    Syrio Forel escaped and became a mathematician.

    • @NotMeInc
      @NotMeInc 9 лет назад +3

      ***** BUT NOT MINE!

  • @GuiltyGearRockYou
    @GuiltyGearRockYou 10 лет назад +61

    my formula is:
    1 diveded by (15+(X*8)) and X is the number of which circle you wanna no the ratio... and the first one is Nb=0

  • @AnkhArcRod
    @AnkhArcRod 5 лет назад +5

    I was wondering as to how many people figured out at one glance that the radius of the inverted blue circles was in fact R/16. He totally glossed over that detail. It is a fun little exercise to confirm that it is indeed the case.
    Also, following this derivation, it is not that difficult to arrive at the general form for the nth circle radius. This has to be one of the sweetest numberphile video I have watched!

  • @mscottveach
    @mscottveach 8 лет назад +102

    Dude is by far the best Numberphile guest.

  • @yellowmeerkat97
    @yellowmeerkat97 10 лет назад +7

    I love this guy so much, he's one of my favorite people that Brady interviews. Everyone he interviews obviously loves what they do and is amazing, but Mr. Pampena's enthusiasm is infectious.

  • @easementh
    @easementh 10 лет назад +23

    This is the firat time I truely craved the brown paper as art for my wall.

  • @KipIngram
    @KipIngram 5 лет назад +3

    Of course, you can give the next number in the sequence immediately, just by noting that the denominator increments by 8 more each time. 23-15=8, 39-23=16, 63-39=24, and so 95-63=32 --> 95 is the next denominator. But nonetheless, this was just an incredibly fun video, and our man's enthusiasm is just amazing and contagious.

  • @bcn1gh7h4wk
    @bcn1gh7h4wk 10 лет назад +120

    ok, now add the 3rd dimension...... I dare you.

    • @ifcoltransg2
      @ifcoltransg2 7 лет назад

      People seem to stop when they get to three.

  • @Theatheosis
    @Theatheosis 10 лет назад +47

    Where's the CPGgrey "first" comment? :P

  • @StormwaterIsOneWord
    @StormwaterIsOneWord 10 лет назад +106

    Most of the videos I can follow...But this, yikes!

  • @sp10sn
    @sp10sn 4 года назад +11

    18:06 "... these two circles are lines ..." was about where slipped out of consciousness

  • @plebeianian
    @plebeianian 10 лет назад +84

    But why is it 1/15? :(

  • @DaviddeKloet
    @DaviddeKloet 10 лет назад +70

    At 22:17 he just states that the blue circle is R/16 without any proof or reasoning. :-(

  • @vivavaldez87
    @vivavaldez87 9 лет назад +255

    All the touching and kissing, I got lost and ended up touching myself :(

    • @prae197
      @prae197 9 лет назад +43

      Did you tangentially touch yourself?

    • @vivavaldez87
      @vivavaldez87 9 лет назад +31

      Zachary Mitchell Very, very tangentially...

  • @zachb.4429
    @zachb.4429 3 года назад +6

    I am not at all exaggerating when I say that this video was what put me on the path to becoming a math major. Thank you

  • @DanielDeVito89
    @DanielDeVito89 10 лет назад +44

    Started losing me around the 15 minute mark when you were talking about the placement of the inverted circles. Maybe I just didn't pay enough attention, but I feel like it wasn't properly explained for someone who's never seen this before.

  • @applemoose9675
    @applemoose9675 6 лет назад +162

    If you raise each term of that sequence to the power of -1, then add 1 to it, then divide it by 8, you get the Fibonacci sequence starting at the term of 2.

    • @vvalph9483
      @vvalph9483 5 лет назад +6

      lol i thought the same thing

    • @linkAKAdude
      @linkAKAdude 5 лет назад +28

      I thought of Fibonacci numbers at first also, but the denominators seem to follow triangular numbers (times 8 then plus 15) which is how I predicted the 95 in the beginning.

    • @guillaume5313
      @guillaume5313 4 года назад +3

      @@linkAKAdude the first few denominators also seem to have a wierd pattern: the nth term is the sum of the two previous terms +1, but that doesn't work for 1/95 though, is there a particular reason for that or just a coincidence?

    • @whywelovefilm7079
      @whywelovefilm7079 4 года назад +4

      Are you all serious? Or speaking nonsense just to be funny?

    • @guillaume5313
      @guillaume5313 4 года назад +7

      @@whywelovefilm7079 We're simply pointing out weird patterns, most of them are probably useless but asking questions is how maths work

  • @iambensummers
    @iambensummers 9 лет назад +24

    To all those saying, "Just add multiples of 8 to the denominator," this video solves the problem in a manner ancient mathematicians like Euclid would have done. Back then, they saw numbers arise from geometry, not the other way around. Basically, this video solves with geometry, not algebra.

    • @johncameron1935
      @johncameron1935 7 лет назад +2

      Ben Summers thank you for this. I solved algebraically in about a minute of paused staring at the sequence. I was so happy that I got it right, unlike with the -1/12 thing.

  • @Arthur-yf9yv
    @Arthur-yf9yv 5 лет назад +58

    I've learned something new today:
    Complex maths makes me cry.

    • @mariuswisser1555
      @mariuswisser1555 5 лет назад +2

      Just my thoughts

    • @clockworkkirlia7475
      @clockworkkirlia7475 4 года назад +5

      Oh, this isn't *complex* maths, precisely... "i" shudder to think. :p

    • @clockworkkirlia7475
      @clockworkkirlia7475 3 года назад +1

      @@merge3550 Oh, that's okay, I can probably do something silly (yet strangely elegant) with exponents to fix it.

  • @5nefarious
    @5nefarious 10 лет назад +22

    Mathematics: surprisingly erotic...

  • @justcarcrazy
    @justcarcrazy 10 лет назад +28

    I'll have to watch this several times more...

  • @Chuuuulet
    @Chuuuulet 10 лет назад +17

    The next term will be 1/135. This is because the formula for the sequence is a quadratic reciprocal. an=1/(4n^2 - 4n + 15)

  • @AnonW
    @AnonW 5 лет назад +22

    And this is how Alfa Romeo came up with their wheel design

  • @qorilla
    @qorilla 10 лет назад +52

    Now Brady! Look Brady!

  • @DaFish1337
    @DaFish1337 10 лет назад +24

    Boy this guy surely is enthusiastic about his circles!

  • @xfusee
    @xfusee 10 лет назад +13

    I've never rooted so strongly for someone to draw a good circle before now

  • @hiimapop7755
    @hiimapop7755 4 года назад +3

    Watched this when I was still young at 2016, so I didn't understand much, thinking that it wasnt that impressive. Watching this video again made me realize how amazing this actually is. Dayum.

  • @ic8575
    @ic8575 9 лет назад +16

    "This is the best time I've done it."
    "That's nice."

  • @HexerPsy
    @HexerPsy 10 лет назад +39

    dang it... 1/94 sooo close XD
    rechecked my calculation and made an ERROR OMG DX
    15 - 23 - 39 - 63 - ?
    differences between those numbers:
    8 - 16 - 24 - ?
    differences between those:
    8 - 8 - ?
    assume the last one is also 8:
    8+24=32
    32+63=95
    answer=1/95
    just a guess, no clue why it works o.0

  • @kelph1
    @kelph1 10 лет назад +4

    Also, if you look at the correlation between 15,23,39,63 you notice that the numbers increase with ascending multiples of 8...
    15+8=23
    23+16=39
    39+24=63
    63+32=95

  • @nickp3949
    @nickp3949 5 лет назад +135

    I thought the title of the video was the guys's name: Eric Circles
    I'm not that bright lol

  • @Niklback1
    @Niklback1 10 лет назад +59

    Where is CGPGrey's first?

    • @LostLargeCats
      @LostLargeCats 8 лет назад

      +Niklback1 Yeah I just started listening to HI.

    • @ghillies3796
      @ghillies3796 5 лет назад

      At the bottom just keep digging

  • @Rararawr
    @Rararawr 10 лет назад +88

    That was an interesting but horribly inefficient method of solving that. Took me a few seconds to answer.
    15+8=23
    23+16=39
    39+24=63
    63+32=95
    I saw a simple pattern quickly and that made this really easy.

  • @Gregmaster
    @Gregmaster 8 лет назад +675

    I just started the vid and the question to your answer is 1/95th this is bc 23-15=8 then 39-23=16 and then 63-39=24 this is going by 8 each time so 24+8=32 and 32+63=95 so the answer is 1/95th

    • @benjaminburgess8476
      @benjaminburgess8476 8 лет назад +125

      That's what I did too. I could make him a nice iterative function that would save a lot of paper and time :) but of course that would just spoil things

    • @Gregmaster
      @Gregmaster 8 лет назад +35

      +Benjamin Burgess All the circle equations was unnecessary work lol

    • @Gregmaster
      @Gregmaster 8 лет назад +17

      +Benjamin Burgess your equation would be ax=8x+7

    • @creater650
      @creater650 8 лет назад +214

      +Greg master It isn't unnecessary, it is beautiful.

    • @jaredmedlin2661
      @jaredmedlin2661 8 лет назад +31

      question to your answer
      (wut)

  • @darthlaan2538
    @darthlaan2538 5 лет назад +5

    This is why mathematicians+graphing programs=LOVE.
    I'm sure it's the same feeling as when Lotus 1-2-3 came out for the accountants.

  • @nictheman144
    @nictheman144 10 лет назад +33

    It's like a calculus with circles. Circulus!

  • @mercybellafiore3677
    @mercybellafiore3677 9 лет назад +52

    2:26 It's a big touch-fest today. 0.o

    • @georgewang2947
      @georgewang2947 8 лет назад +24

      Do you know how hard it is to get four circles to kiss?

    • @Ozibiey
      @Ozibiey 8 лет назад +3

      +George Wang It's not straight, that's for sure! ;)

    • @ender_scythe2879
      @ender_scythe2879 8 лет назад +1

      +Ozibiey circles have no gender...

  • @GigaBoost
    @GigaBoost 10 лет назад +44

    I have no idea what this means, the process is long as fuck and doesn't seem to work anything out that couldn't be measured with a ruler

  • @archivist17
    @archivist17 5 лет назад +9

    Beautiful! I love explanations where I get lost, but end up understanding.

  • @MrThebradon2001
    @MrThebradon2001 10 лет назад +25

    Math is art...

  • @illustriouschin
    @illustriouschin 10 лет назад +70

    23-15=8, 39-23=16, 63-39=24, 95-63=32. pretty easy to find the pattern here. I got the answer without spending countless hours killing myself staying up all night trying to figure out the circles shit which he only partially described.

  • @BenadrylNumbercrunch
    @BenadrylNumbercrunch 8 лет назад +12

    i hope one day i can be as passionate about anything as that man is about circles

  • @davecrupel2817
    @davecrupel2817 3 года назад +2

    There's something really gratifying, satisfying and fulfilling about seeing you folks do mathematics in these comments. It feels like you're using your keyboards to the extreme. Flexing almost. While having fairly enlightening, very intelligent, nerdy conversations! And as a nerd myself, i love it!