New Recipe for Pi - Numberphile

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  • เผยแพร่เมื่อ 5 ก.ย. 2024
  • Interview with Sinha & Saha at • Pi-oneers (interview w... and the extra physics bit is at • New Pi Formula (the ex... --- More links & stuff in full description below ↓↓↓
    This video features Tony Padilla: www.nottingham...
    Arnab Priya Saha & Aninda Sinha are based at the Centre for High Energy Physics, Indian Institute of Science - chep.iisc.ac.in
    The paper on Physics Review Letters: journals.aps.o...
    And on arxiv: arxiv.org/abs/...
    The press release: iisc.ac.in/eve...
    The Case for String Theory (Sixty Symbols): • The Case for String Th...
    Numberphile's Pi Playlist: • Pi on Numberphile
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ความคิดเห็น • 922

  • @numberphile
    @numberphile  หลายเดือนก่อน +74

    Extra Physics Bit: th-cam.com/video/AZxoENTRKxg/w-d-xo.html
    Interview with Sinha and Saha (the authors): th-cam.com/video/2lvTjEZ-bbw/w-d-xo.html
    Sixty Symbols (our physics channel): th-cam.com/users/sixtysymbols
    Pi Playlist: th-cam.com/play/PL4870492ACBDC2E7C.html

  • @Peregringlk
    @Peregringlk หลายเดือนก่อน +909

    7:32
    - Tony: the 105th trillionth digit of PI is 6.
    - Brady: good to know

    • @Rubrickety
      @Rubrickety หลายเดือนก่อน +40

      I loved that moment.

    • @FLScrabbler
      @FLScrabbler หลายเดือนก่อน +100

      I was 10% sure it would be. How nice that it has been confirmed..! 😇

    • @nemecsek69
      @nemecsek69 หลายเดือนก่อน +28

      With a certainty of 50%, the next one is between 0 and 4 included.

    • @aceman0000099
      @aceman0000099 หลายเดือนก่อน +17

      How do they know this chudnovski formula doesn't deviate at 89 trillion digits or something? Don't you need another algorithm of equal or superior accuracy to verify?

    • @phizc
      @phizc หลายเดือนก่อน +16

      I think you only need around 62 digits of PI to calculate the circumference of the universe from its radius and only be off by a Planck length. More digits are just for bragging rights, and measuring computer speeds. Nothing wrong with that of course. 😅
      Also, the universe is expanding, so we'll need another digit in about 86 bn years.
      Not sure if my math is correct:
      14 bn LY is about 10²⁶ meters.
      10²⁶/10⁶² = 10^-36
      Planck length = 1.6 * 10^-35

  • @dhoyt902
    @dhoyt902 หลายเดือนก่อน +739

    Lifelong Pi mathematician here. It does have to do with circles. Chudnovsky specifically has to do with circles, in the complex plane, using hyperbolic geometry, using 163i as its basis. Ramunujan's is the same, but for 1i. You can make single series reps of pi with ramanujan sato series with all the Heegner numbers 1,2,3,7,11,19,43,67,163. You can make infinite ramunjan sato series if you allow multiple sums. There is ALWAYS a circle, lol.

    • @aniketdhumal2692
      @aniketdhumal2692 หลายเดือนก่อน +21

      Bro half the "mathematicians" on numberphile are so confidentially incorrect

    • @SilverLining1
      @SilverLining1 หลายเดือนก่อน +139

      ​@@aniketdhumal2692They're not confident though? Does "I don't know" and "maybe" and "I think" sound like someone brimming with confidence or someone making an educated guess? FWIW, pi rarely has to do with circles. Even in complex analysis, where you can correctly claim pi being a factor of a residue is due to integrating over a circle, it's just not that helpful the deeper you go.
      Frankly, since numberphile typically only talks about recreational mathematics and undergraduate mathematics, it's extremely rare for them to even have to chance to be wrong about something. It really says a lot about you if you can comment something like that in spite of this.

    • @aniketdhumal2692
      @aniketdhumal2692 หลายเดือนก่อน +8

      @@SilverLining1 you say this but there's obvious problems in many of these videos. Heck Mr. Parker is known to make mistakes. Kinda cute how you say this is easy maths and still have shitton of faults every other video lol

    • @fussyboy2000
      @fussyboy2000 หลายเดือนก่อน

      Does this mean the formulae converge to 1/pi when an infinite number of terms are taken?

    • @hylens5111
      @hylens5111 หลายเดือนก่อน +1

      I'll take your word for it.

  • @fonkbadonk5370
    @fonkbadonk5370 หลายเดือนก่อน +223

    I never want this channel to end. Brady and I are roughly similarly aged, and if I'm refreshing my YT subs page at 80 and there aren't any new videos, I'm just gonna lay down for good.

    • @Life_42
      @Life_42 หลายเดือนก่อน +9

      Best math channel in my opinion.

  • @Sandeepan
    @Sandeepan หลายเดือนก่อน +329

    I went to school with brother Arnab, was two batch junior.
    He was already a local legend in that area when it comes to maths back in 2009

    • @DadgeCity
      @DadgeCity หลายเดือนก่อน +7

      A legend, you mean :)

    • @Irondragon1945
      @Irondragon1945 หลายเดือนก่อน +51

      @@DadgeCity No, an urban legend.
      He roams the underground pipe network at night like an alligator

    • @Sandeepan
      @Sandeepan หลายเดือนก่อน +30

      @@Irondragon1945
      And was always thirsty for novel math problems

    • @RonJohn63
      @RonJohn63 หลายเดือนก่อน +1

      What's a batch junior?

    • @giftsonvethanayagam2963
      @giftsonvethanayagam2963 หลายเดือนก่อน +13

      @@RonJohn63 Indian way of saying, Two grades behind 😂😂

  • @muskyoxes
    @muskyoxes หลายเดือนก่อน +202

    The cool thing about the Indian series 1 - 1/3 + 1/5 ... is that it had an error term that vastly increased its usefulness. After ten terms, the sum is way off (3.04) but the error term ((n^2+1)/(4n^3+5n)) zooms it right to 3.14159270

    • @AureliusR
      @AureliusR หลายเดือนก่อน +13

      Where does that error term come from?

    • @ninadgadre3934
      @ninadgadre3934 หลายเดือนก่อน

      @@AureliusRmathologer has an excellent video explaining this exact thing, do check it out!

    • @muskyoxes
      @muskyoxes หลายเดือนก่อน +28

      @@AureliusR the Madhava_of_Sangamagrama wiki page speculates it was from working with continued fractions

    • @MABfan11
      @MABfan11 หลายเดือนก่อน +10

      task failed successfully

  • @4GENS
    @4GENS หลายเดือนก่อน +20

    Every time I think of a question the camera man asks it, it's so helpful

    • @therabbithat
      @therabbithat หลายเดือนก่อน

      Yes, or when I haven't thought of it, it's always a great question

    • @johnnye87
      @johnnye87 หลายเดือนก่อน +1

      Except for my question "where that graph peaks at lambda = 3 and a bit, is THAT pi ???"

  • @billferner6741
    @billferner6741 หลายเดือนก่อน +60

    In earlier days of PC programming (80s 90s), the BASIC did not have pi included. To get it with the program prcision, we used the atan(1)*4

    • @MichaelPohoreski
      @MichaelPohoreski หลายเดือนก่อน +3

      Which is rather ironic since AppleSoft BASIC has 1/2 PI and 2PI constants in ROM.

    • @faustobarbuto
      @faustobarbuto หลายเดือนก่อน

      @@billferner6741
      Same same with FORTRAN-77.

    • @dielaughing73
      @dielaughing73 หลายเดือนก่อน +4

      And where did it get atan(1) from?

    • @BetaDude40
      @BetaDude40 หลายเดือนก่อน +10

      Most likely a function call for some n iterations of the taylor series expansion of arctan(1)

    • @firstname4337
      @firstname4337 หลายเดือนก่อน +1

      @@MichaelPohoreski LOL @ you not knowing what "ironic" means

  • @rosiefay7283
    @rosiefay7283 หลายเดือนก่อน +64

    6:41 640320^{3k}. Shades of exp{π√163}~~640320^3+744.

    • @donweatherwax9318
      @donweatherwax9318 หลายเดือนก่อน +7

      Hey you're right! Lol!
      (just kidding, no idea what you said)

    • @Jochen666
      @Jochen666 หลายเดือนก่อน

      @@donweatherwax9318 😂

    • @vaakdemandante8772
      @vaakdemandante8772 หลายเดือนก่อน

      interesting observation, when viewed in WolframAlpha with /input?i=exp%28%CF%80%E2%88%9A163%29-%28640320%5E3%2B744%29 it gives error of only around 10^-12.

    • @Alex_Deam
      @Alex_Deam 25 วันที่ผ่านมา +1

      Not a coincidence, the results are connected!

    • @Alex_Deam
      @Alex_Deam 25 วันที่ผ่านมา

      @@vaakdemandante8772 It's called the Ramanujan constant, it's actually a very famous result. It's connected to a lot of deep areas, but Numberphile have a vid introducing it (called "163 and Ramanujan Constant"). The Wikipedia page on "Heegner numbers" is also worth a look to go deeper and work out what to google if you're interested.

  • @jesusthroughmary
    @jesusthroughmary หลายเดือนก่อน +328

    Last time I was this early the Parker Square was just an erroneous attempt at a magic square

    • @The.171
      @The.171 หลายเดือนก่อน +4

      Lo

    • @Nachiebree
      @Nachiebree หลายเดือนก่อน +11

      And this is just Parker's Pi

    • @samlevi4744
      @samlevi4744 หลายเดือนก่อน +6

      At least he never lied to us about things being equal to -1/12. I think.

    • @fonkbadonk5370
      @fonkbadonk5370 หลายเดือนก่อน +2

      @@The.171 Since I'm German, YT offered me to translate your comment. Apparently "Lo" in English is "It" in German xD

    • @jesusthroughmary
      @jesusthroughmary หลายเดือนก่อน +1

      @@Nachiebree it kind of is

  •  หลายเดือนก่อน +109

    The Madhava series is a Taylor series for arctan(1). I wonder whether this new representation is also a Taylor series of some kind

    • @trueriver1950
      @trueriver1950 หลายเดือนก่อน +19

      It is, but Madhava wouldn't have known that

    • @landsgevaer
      @landsgevaer หลายเดือนก่อน +18

      Add a factor x^n to the sum and you have one.

    • @QuantumHistorian
      @QuantumHistorian หลายเดือนก่อน +13

      @@landsgevaer Bingo. You can turn any series into a function. Whether that function turns out to be useful for anything or related in a meaningful way to existing functions is a different matter all together...

    • @geology-fz3hi
      @geology-fz3hi หลายเดือนก่อน +10

      @@trueriver1950 Madhava did know about the power series expansions of sin, cos, arctan. Madhava founded the Kerala school of mathematics where they discovered differentiation, integration and power series expansions.

    • @geology-fz3hi
      @geology-fz3hi หลายเดือนก่อน +1

      @@trueriver1950 Powell's Pi Paradox

  • @daviddeweger4106
    @daviddeweger4106 หลายเดือนก่อน +8

    I’m unreasonably happy that the length of this video is 14:28

  • @billcook4768
    @billcook4768 หลายเดือนก่อน +28

    IIRC, if you had two circles, each the size of the universe, one based on pi and one based on an approximate value of pi, you only need about 60 digits of approximate-pi for the two circles to be exactly the same. Any theoretical difference would be smaller than the Planck length, the smallest possible distance in the fabric of space.

    • @MichaelPohoreski
      @MichaelPohoreski หลายเดือนก่อน +4

      Planck Length is *believed* to be the smallest possible distance but modern Scientists have nothing even _close_ to measuring this (several order of magnitude off.)

    • @orlock20
      @orlock20 หลายเดือนก่อน +6

      When working with machinery, it's four places. That's because of material breakdown and at the microscopic level the line is still jagged, but not to a point where it structurally matters.

    • @MichaelPohoreski
      @MichaelPohoreski หลายเดือนก่อน +2

      @@orlock20 You wouldn't happen to know what tolerances are mil-spec grade by chance? Not looking to reading AS9100 spec. :-)

    • @orlock20
      @orlock20 หลายเดือนก่อน +2

      @@MichaelPohoreski The highest accuracy mentioned for anything was .00001 and that was used as a joke.

    • @v2ike6udik
      @v2ike6udik หลายเดือนก่อน

      @@MichaelPohoreski it is not smallest. it where grabiti and other forces, are equal or smth. it is never ending zoo of "particles", that do not really excist. and are figment of imagination.

  • @ajsmith7619
    @ajsmith7619 หลายเดือนก่อน +6

    Tony's enthusiasm and his ability to communicate a complicated subject to duffers like me, make him a must watch.

  • @AnimusInvidious
    @AnimusInvidious หลายเดือนก่อน +23

    Paper change interludes always make me happy.

    • @ADITYA-qt8zd
      @ADITYA-qt8zd หลายเดือนก่อน

      he eh ehe e eeeeehe

  • @Xelianow
    @Xelianow หลายเดือนก่อน +48

    I imagine the optimal lambda values require pi in the first place by beeing a transcendental number themself, which would require knowing pi in the first place to calculate (or better: approximate) that optimal lambda...
    Edit: Nevermind, they definitly *are* transcendental numbers, since they are simply rational multiples of pi.

    • @SilverLining1
      @SilverLining1 หลายเดือนก่อน +1

      Only for the truncated series. I don't think there's a particular reason that the rate of convergence as a function of lambda should have an extremum at values of lambda that are finite expressions involving pi. But, they might.

    • @Xelianow
      @Xelianow หลายเดือนก่อน +2

      @@SilverLining1
      Well, if you don't truncate the rate of convergence is pretty much irrelevant, because without truncation it will simply give you the exact value of pi regardles of lambda. How fast it converges does not matter when the process is infinite...

    • @rrrrog
      @rrrrog หลายเดือนก่อน +3

      It would be cool if you found a formula that gets close to finding the optimal value of lambda given an approximation of Pi, so that you could just alternate between the two formulas to get closer and closer.

  • @cyrilio
    @cyrilio หลายเดือนก่อน +12

    If pie is the meal then the series is the recipe.
    Lovely way of describing a math formula.

  • @kalla103
    @kalla103 หลายเดือนก่อน +4

    i love your editing style and how your videos stayed consistent throughout the years. great work!

  • @QuantumHistorian
    @QuantumHistorian หลายเดือนก่อน +86

    I'm incredibly shocked that science (/maths) journalism would overhype and completely misrepresent a technical result. Well, ok, not that shocked. Not shocked at all really.

    • @talastra
      @talastra หลายเดือนก่อน +4

      Don't be shocked. Here you are on the video.

    • @nozua
      @nozua หลายเดือนก่อน +7

      Yeah that shouldn't come as a surprise whatsoever. I hate journalists so much it's unreal.

    • @BetaDude40
      @BetaDude40 หลายเดือนก่อน

      You should be hating the advertisers and executives who have turned journalism into the farce it is to get more outrage bait and clicks for revenue

    • @ianstopher9111
      @ianstopher9111 หลายเดือนก่อน +9

      From what I recall, it was only hyped in India. It is an interesting aside and the authors downplay its overall importance. It is novel, and a little interesting, but currently does not offer much, compared to Chudnovsky.

  • @xyzct
    @xyzct หลายเดือนก่อน +31

    Brady, the gawking rabble demands an explanation of where Ramanujan's and Chudnovsky's series come from.

    • @Talon19
      @Talon19 หลายเดือนก่อน +6

      This!
      Sure, the equation is fairly simple, precise, and accurate; but WHY does it work?

    • @xyzct
      @xyzct หลายเดือนก่อน +6

      @@Talon19, and how did they arrive at it???

    • @why-ak
      @why-ak หลายเดือนก่อน +1

      Not sure if this true but I have the legend that Ramanujan saw this formula conjured into his mind. To be honest somehow I find this much more believable than actually the guy trying to find a formula with a summation and factorials. But man I see your point, it is mind bending to think how these formulae came!

    • @sphynx3902
      @sphynx3902 หลายเดือนก่อน +1

      Ramanujan himself had said the formula came to him in his dreams

    • @KarmaFeline
      @KarmaFeline หลายเดือนก่อน +2

      Shut it mortal, It was revealed to me by the universe.

  • @jesusthroughmary
    @jesusthroughmary หลายเดือนก่อน +165

    Brady was correct that there must be an irrational value of lambda which yields pi exactly with 0 approximation error, but we will never be able to find it

    • @dunda563
      @dunda563 หลายเดือนก่อน +74

      If anything, finding the perfect lambda would require its own method of approximation, and knowing how Pi is it would somehow be defined in relation to it. Finding Pi with Pi is self-defeating, and otherwise improving an approximation with a second harder approximation isn't much better

    • @jesusthroughmary
      @jesusthroughmary หลายเดือนก่อน +26

      @dunda563 yes, I was thinking this is essentially circular reasoning

    • @rantingrodent416
      @rantingrodent416 หลายเดือนก่อน +4

      Yeah, doesn't this method really just provide a convenient container for the magic constants in the other methods? I'm sure you could improve those series further just by finding the right constants, which would be the same as searching for ideal values of lambda here?

    • @grendel_eoten
      @grendel_eoten หลายเดือนก่อน +8

      Successive approximations as a solution are not necessarily useless. See: Kepler's equation

    • @scaredyfish
      @scaredyfish หลายเดือนก่อน +7

      I have a formula for Pi that is a really close approximation after one term, but never improves after that.

  • @funnyman359
    @funnyman359 หลายเดือนก่อน +9

    Something that wasn't addressed in this video is that (from their appearance at least), the first 4 terms of each series are way way different in how complex it'd be to compute them. I wonder which series fares better with e.g. 1 minute or 10 minutes etc. of computation time, since some of these contain huge factorials or exponential terms.

  • @moebadderman227
    @moebadderman227 หลายเดือนก่อน +3

    @5:19
    My favourite Ramanujan approximation is π ≈ (355/113)(1 - 0.0003/3533), with relative error less than one-half part per quadrillion. I found this years ago (don't remember where), wrote it in my reference book, and have not found a source.

  • @ScorelessPine
    @ScorelessPine หลายเดือนก่อน +10

    One bit I'm curious about, when he says they've set a record for number of digits of pi calculated using the Chudnovsky formula, how do they *know* for certain at what digit they've accurately calculated, if they know that it's an approximation? My assumption would be that in order to know for certain that a calculated digit is correct, you'd need to go some level further to confirm it? Is it basically that you would need a calculation using N terms, then calculate the N+1'th term and the position of the first nonzero term gives you the confirmation of the last known-accurate digit? If all it takes is a known calculation/approximation at N terms and adding the N+1 term, that makes me wonder at *actually* how much computation time it takes for a supercomputer to determine the next term, it must be way more than I'd initially expect.

    • @AnalKumar02
      @AnalKumar02 หลายเดือนก่อน

      There are other ways to get the approximation of pi. Search for Spigot algorithm

    • @-danR
      @-danR หลายเดือนก่อน +1

      This is the first puzzle that struck me about this video. The second puzzle, even more puzzling, is why do they not even _address_ this puzzle? Provability is the obsession of Mathematics.
      The third puzzle is the near-absence of puzzlement about it in the comment section.

    • @captaindunsell8568
      @captaindunsell8568 26 วันที่ผ่านมา

      They should be validated against each other… inaccurate use on earth tethered activity isn’t a problem, but celestial activities could be disastrous over great distances

  • @rosiefay7283
    @rosiefay7283 หลายเดือนก่อน +86

    I wonder how Madhava found that the limit of 1-1/3+... is π/4. I mean, it is, but the series converges so slowly that he couldn't have got all that close to π/4 with as many terms as he'd be able to sum using 14th-century tech.

    • @tusharsharma7513
      @tusharsharma7513 หลายเดือนก่อน +6

      I believe, persistence

    • @asheep7797
      @asheep7797 หลายเดือนก่อน +9

      If you look further, he actually used correction terms that basically boost the accuracy of the result.
      This can be seen in action with:
      4(1/1-1/3+1/5-1/7+1/9-1/11+1/13) = 3.2837...
      4(1/1-1/3+1/5-1/7+1/9-1/11+1/13-1/(13*2-2)) = 3.1408...

    • @thomasr2472
      @thomasr2472 หลายเดือนก่อน +50

      Madhava didn't manually add up numbers, he discovered power series of trigonometric functions. Plug x=1 into the arctan series atan(x)=x-x^3/3+x^5/5-x^7/7… and voilà.

    • @amits4744
      @amits4744 หลายเดือนก่อน +19

      3 Blue 1 Brown proved the Madhava series in a easy to understand way in 1 of his videos

    • @sgiri2012
      @sgiri2012 หลายเดือนก่อน +4

      We are actually talking about the approximation of decimal places of pi.but what is the exact decimal places of pi ? How is it even calculated? How we can prove that the approximations actually approximating the decimal expansion of pi

  • @FenceThis
    @FenceThis หลายเดือนก่อน +3

    the good old 355/113 compared to the often taught 22/7 has a deviation from pi of 2.66/10 000 000 compared to 1.26/1000
    which translates to a watch running less than 8.5 secs wrong per year compared to more than 11 hours

  • @SuspenduAuGaffa
    @SuspenduAuGaffa หลายเดือนก่อน +7

    3:14 (Well, about there, but I fancied using that timestamp 😉): How is Ramanujan's formula useful in practice? That √2 at the beginning seems to make life difficult, as the square root needs a good approximation before you can even start.

    • @Biosynchro
      @Biosynchro หลายเดือนก่อน +1

      Not being a mathematician, I never noticed that. But darn tootin', I think you're right. Using one irrational number to define another one? Is that even valid? Far from it for me to question Ramanujan, but you really got me thinking.

  • @Rocksite1
    @Rocksite1 หลายเดือนก่อน +2

    I suppose, from a computer scientist's POV, that the real question about any of them, is not how many iterations it takes to get n digits of pi, but how "expensive" the mathematical operations are. E.g. factorials become more expensive than exponents. Thus, one needs to figure out how many additions, subtractions, multiplications, relatively expensive divisions and exponents are required for at least n digits.

  • @DiCasaFilm
    @DiCasaFilm หลายเดือนก่อน +16

    I can’t be the only one who’s wondering what happens if Lambda is equal to Pi.

    • @i_rish_0
      @i_rish_0 หลายเดือนก่อน +1

      He mentioned Lambda should be a convergent series. Pi is a divergent series.

    • @Tumbolisu
      @Tumbolisu หลายเดือนก่อน +13

      @@i_rish_0 Numbers themselves are neither divergent nor convergent. He said that basically any number can be used for lambda, as long as the series converges. You can see from the graph that lambda = 0 does not yield a converging series - it shoots up to infinity.

    • @plwadodveeefdv
      @plwadodveeefdv หลายเดือนก่อน +1

      isn't it on the graph, between 0 and 4?

  • @nilsp9426
    @nilsp9426 หลายเดือนก่อน +76

    What if you normalized the efficiency of the different approximations by looking at the number of basic operations (i.e. computation time) instead of the number of iterations?

    • @lucasvignolireis8181
      @lucasvignolireis8181 หลายเดือนก่อน +7

      i was thinking about that ...

    • @ericrosen6626
      @ericrosen6626 หลายเดือนก่อน +1

      I should have known better than to post before reading (the small number) of comments...

    • @disonaroaurelo
      @disonaroaurelo หลายเดือนก่อน

      The most important thing obtained was the new form of geometric manipulation.

    • @mysteryprize
      @mysteryprize หลายเดือนก่อน +5

      Yeah, that to me is the more interesting question, because I don't think anyone's seriously going to be doing these by hand (beyond perhaps a few iterations). So that suggests a representation can be considered 'better' either because it is more efficient in number of operations for a computer, or because it is more easily parsed/calculated by an unaided human.

    • @QuantumHistorian
      @QuantumHistorian หลายเดือนก่อน +14

      The problem is that depends on your computer architecture, so it's not an abstract mathematical analysis. But considering that Chudvosky is a thousand billion billion billion times more accurate than Ramanudjan using the same number of terms (at n=4 anyway), you can afford spending a little bit more time per step.

  • @fusion67
    @fusion67 หลายเดือนก่อน +20

    7:28 I wanna know what k value they went up to in order to get 100 trillion digits

    • @nilsp9426
      @nilsp9426 หลายเดือนก่อน +4

      Honestly, the computation time with increasing k for this equation looks kind of nasty, so maybe not even that high.

    • @ckq
      @ckq หลายเดือนก่อน

      Why? We have Stirling's approximation for factorials

    • @Ultras743
      @Ultras743 หลายเดือนก่อน +1

      Chudnovsky formula calculated an average 14.1816 decimal digits of pi per iteration

  • @ruferd
    @ruferd หลายเดือนก่อน +10

    11:04
    I saw a different video where another commentor pointed out that lamda =1,2,3,... Has increasing accuracy for pi, but lamba=iinfinity converges super slow, so its nice to see the "best" values for lamda to converge quickly.

  • @louisng114
    @louisng114 หลายเดือนก่อน +58

    I challenge anyone to find a series that approaches π more rapidly:
    π + 0 + 0 + 0 + ...

    • @unvergebeneid
      @unvergebeneid หลายเดือนก่อน +1

      I think you're only allowed to use known quantities... 🤔

    • @billcook4768
      @billcook4768 หลายเดือนก่อน +23

      Obviously it’s cheating to use pi to calculate pi. I’d go with tau/2 + 0 + 0 + 0…

    • @Kunsho1
      @Kunsho1 หลายเดือนก่อน +7

      @@unvergebeneidI've come up with a formula so neat that it coverges to trillion digits of Pi with its first term. And it's just an integer divided by 10^trillion, how cool is that?

    • @canyoupoop
      @canyoupoop หลายเดือนก่อน

      As mr. Incredible rightly said, "PI IS PI!!!"

    • @adaroben1104
      @adaroben1104 หลายเดือนก่อน

      Unfortunately I think "approaches" pi disqualifies it since it never changes.

  • @johannesvanderhorst9778
    @johannesvanderhorst9778 หลายเดือนก่อน +1

    Interesting to see that we (still) use just infinite series to calculate digits for pi. Because I knew of the existence of two other modern ways:
    Iterative algorithms. A computer program that takes initial values for some variables, and at each iteration changes the values for these variables to better approximate pi. In general each iteration doubles the number of accurate digits.
    Spigot algorithms. They look like just infinite series. But their advantage is that one can compute any digit for pi without needing to compute any preceding digit for pi (in the right base what is not necessary base 10.)
    Also, in the converging series I see in this video I see square roots, and they must be computed as well with high accuracy.

  • @Checkmate12342
    @Checkmate12342 หลายเดือนก่อน +4

    indian Acharya Madhav was really shocking for me how he discovered and purposed the infinite series of all trigonometric functions at that time when calculus was not invented and so many undiscovered things ????

  • @RUBBER_BULLET
    @RUBBER_BULLET หลายเดือนก่อน +25

    I'll stick with 22/7.

    • @Biosynchro
      @Biosynchro หลายเดือนก่อน

      Four ASCII characters - the shortest definition of pi you'll ever get!

    • @Deathington.
      @Deathington. หลายเดือนก่อน +2

      22/7 is not actually pi

  • @AlRoderick
    @AlRoderick หลายเดือนก่อน +4

    This is great because chef John at food wishes posted a recipe for peach pie on the same day.

  • @Rubrickety
    @Rubrickety หลายเดือนก่อน +3

    In this video Tony showed several methods for approximating the digit 4.

  • @cozynancy
    @cozynancy หลายเดือนก่อน +3

    This was fun to watch! Thank you for the video. ❤

  • @OnlyFactsAndData4829
    @OnlyFactsAndData4829 หลายเดือนก่อน +2

    Wow! The numberphile logo looks more beautiful now!

  • @dvr007
    @dvr007 หลายเดือนก่อน +10

    That “good to know” from Brady left me cracking 😂

  • @anoriolkoyt
    @anoriolkoyt หลายเดือนก่อน +1

    At 11:42 Brady raised a good question that I dont think was answered. The fact that lamba goes from positive to negative indicates that there is a value for which the calculation provides a 0% deviation. Indeed, for a few values of lambda, the deviation is absolute 0. Or perhaps if we zoomed in more we would find some asymptopes that lamba tends to infinitely small?

  • @ericrosen6626
    @ericrosen6626 หลายเดือนก่อน +3

    I'm paused at 6:36 -- while the Madhava series takes a lot more terms to get close, it is also significantly simpler than the Ramanujen and Chudnovsky series. Would be interesting to compare the actual computational power required to get to n-digits of accuracy.

    • @trueriver1950
      @trueriver1950 หลายเดือนก่อน

      One way to do this would be to time the program, and take the last value found before the given time.

    • @Ryan_Thompson
      @Ryan_Thompson หลายเดือนก่อน +3

      Computer scientist here. The Madhava series takes way, *way* more terms and computation time for any non-trivial result. It converges extremely slowly compared to the Chudnovsky series.
      In computer science terms, Chudnovsky converges with O(n(log n)^3) complexity. A million digits takes 216 million terms. Ten digits takes just ten terms.
      Can't recall the exact complexity, but Madhava is far, far worse. Calculating just ten digits of pi requires billions of terms. And the difference grows faster than linear, so no amount of linear constant complexity would make up for the difference.
      Someone can double check my math, as it's real early in the morning here, but having implemented both algorithms in the past, I'm confident the flavor is at least correct. I can tell you Madhava converges very, very slowly. It's possible to use correction terms which help things quite a bit (enough to feasibly get hundreds of digits) but it's still nowhere near Chudnovsky.
      Hope this helps.

    • @ericrosen6626
      @ericrosen6626 หลายเดือนก่อน +1

      Madhava locks in the first decimal place at the 25th term.
      It locks in the second at the 627th term
      The third at 2,454
      The fourth at 136,120
      The fifth at 376,849

    • @wesleydeng71
      @wesleydeng71 หลายเดือนก่อน +1

      Regarding the complexity of the Ramanujen/Chudnovsky series, the terms are basically factorials and powers. This means you don't have to calculate each term from scratch. Rather, you can reuse results from the previous term, which will greatly reduce computing time.

  • @eskay1891
    @eskay1891 หลายเดือนก่อน +2

    Thanks a lot, there is no scratching sound from brown paper anymore.

  • @devesh.....
    @devesh..... หลายเดือนก่อน +3

    IISC representing india ❤❤

  • @dogwithamug
    @dogwithamug หลายเดือนก่อน +1

    the graph shows you can choose lambda to make your approximation as good as you want, even better than chudnovsky, since the graph crosses 0! clearly it crosses 0 for values which are as hard to compute as pi is in the first place, but one can compute an approximation and run with it to get a very quickly convergent series

    • @vsm1456
      @vsm1456 หลายเดือนก่อน

      if these "optimal" lambda values are related to Pi, you can iterarively reuse your calculated Pi digits to produce more and more accurate lambdas

    • @dogwithamug
      @dogwithamug หลายเดือนก่อน

      @@vsm1456 that's an intriguing idea

  • @randyzeitman1354
    @randyzeitman1354 หลายเดือนก่อน +15

    HOW THE F DID RAMU COME UP WITH THAT CRAZY EXPRESSION! ... NEW VIDEO NEEDED!!!!

    • @talastra
      @talastra หลายเดือนก่อน +6

      The goddess told him

    • @ssl3546
      @ssl3546 หลายเดือนก่อน +2

      Smartest guy of the 20th century, killed by British food

    • @Quantris
      @Quantris หลายเดือนก่อน

      @@ssl3546 was he killed by it or did he die to escape it?

  • @PeterPrevos
    @PeterPrevos หลายเดือนก่อน +1

    In Ramanujan's formula you need to know the expansion of the square root of two, which itself is an infinite series.

  • @leefisher6366
    @leefisher6366 หลายเดือนก่อน +20

    1:41 - Madhava of Sangamagrama, eh? Did he know that other vowels were available?

    • @theacorn7240
      @theacorn7240 หลายเดือนก่อน +5

      my indian last and middle name are pretty lengthy and the only vowels are As which constitute every other letter

    • @leefisher6366
      @leefisher6366 หลายเดือนก่อน

      @@theacorn7240 Is there a reason, seriously, for this? Google isn't helping me here.

    • @user-kw6wv7vv8k
      @user-kw6wv7vv8k หลายเดือนก่อน

      It's a transliteration thing. All indian names with an 'uh', 'aa', 'ae' and many such sounds gets simplified simply to just a in English because Hindi has around 14 vowels ​@@leefisher6366

    • @a-bison
      @a-bison หลายเดือนก่อน +1

      ​@@leefisher6366our names stem from Sanskrit.

    • @surya_11
      @surya_11 หลายเดือนก่อน +4

      ​​​@@leefisher6366 So basically you're looking for the "reason" why names in a 7000 years old Eastern civilization don't follow your Anglo standards?

  • @kiro9291
    @kiro9291 หลายเดือนก่อน +2

    0:18 Tony Padilla is my favorite string phenomenologist

  • @mrdraw2087
    @mrdraw2087 หลายเดือนก่อน +5

    Missed an opportunity to bring this video out on July 22nd.

  • @bigknocker2264
    @bigknocker2264 หลายเดือนก่อน

    I discovered a formula for pi/4 that is an alternating infinite series of powers of pi with rational coefficients where the powers of pai vary from 2 to infinity. The implication of this in that if we multiply each side by 4/pi, then any rational number can be represented by an alternating infinite series of powers of pi with rational coefficients when the powers of pi vary from 1 to infinity.

  • @pwolkowicki
    @pwolkowicki หลายเดือนก่อน +5

    "They calculated Pi to 105 trillion decimal places" - I think they should stop at the Planck's lenth.

    • @nHans
      @nHans หลายเดือนก่อน +1

      What exactly did you have in mind? Pi is a dimensionless number from pure math whose decimal representation has an infinite number of digits. Planck Length comes from physics and has the dimensions of length. Its numerical value depends on the units chosen. If you choose Planck Units, the value of Planck Length is exactly 1. But the value of Pi doesn't change-it remains 3.14159… regardless of whatever system of units you choose in physics.

    • @vsm1456
      @vsm1456 หลายเดือนก่อน

      knowing a lot of digits of Pi probably isn't going to help you solve real world problems, but you can use it, for example, to research properties of Pi itself

  • @bradleywilliambusch5198
    @bradleywilliambusch5198 หลายเดือนก่อน

    The natural set (2 direction) of x and y, R^(x,y)_0=10: 3/4*[4+[3^(1/3)/10*2-1/10]]=3.141337, 3-d space is rough.
    (edit) You can subtract the exponential function of x and y, but you can't add it to make it truly two directional, so space 11 is a placeholder.

  • @King0Mir
    @King0Mir หลายเดือนก่อน +1

    It seems unfair to compare the convegence of these three series by comparing how close it is afted 4 iterations, because of the complexity of each iteration. Each iteration of the more complicated series involves more steps. Especially with as low a number as 4. Probably i would count the number of complex operations like division and square root, to accurately portray how quickly each series converges.

  • @nossonweissman
    @nossonweissman หลายเดือนก่อน +7

    Love the title ❤

  • @JohnSmith-zq9mo
    @JohnSmith-zq9mo หลายเดือนก่อน +1

    Discussions on math pages suggest that when you use more terms you get better result with larger values of lambda.

  • @Pathakin.
    @Pathakin. หลายเดือนก่อน +6

    New Flavour!!!

  • @leonhardtkristensen4093
    @leonhardtkristensen4093 หลายเดือนก่อน

    I did calculate Pi once by using triangles and sum them up. It was something like the sum of(r*dx)/2 where x is the circle divided up to infinity. It was about 50 years ago when I studied to become an electronic engineer and had some mathematics. I have long forgotten it though. I am sure some mathematician can write it up correctly immediately. The result should be close to correct.

  • @duhmez
    @duhmez หลายเดือนก่อน +4

    Do all of these example all converge exactly to pi at the limit? Or are some just good approxiomationsas?

    • @joshguan8672
      @joshguan8672 หลายเดือนก่อน

      Yes, they all converge exactly to pi at the limit.
      These can be mathematically proven just like how we proved pi is an irrational number in the first place.
      Exact value of pi is not needed (and impossible to get in the first place) in those proofs.

  • @WereWade
    @WereWade หลายเดือนก่อน +1

    I get so excited to test out this summation after hearing about it a few days back, but then I get to time 1:24 , pause, and I'm like... well what's lamda? Who's solving for second variables in a summation? That's not fair. _Now I'll have to watch the rest of the video._ 🤪

  • @MecchaKakkoi
    @MecchaKakkoi หลายเดือนก่อน +8

    Yum!

  • @marinoceccotti9155
    @marinoceccotti9155 หลายเดือนก่อน +1

    Waaaaaah. String theory bringing something usable...

  • @shaytal100
    @shaytal100 หลายเดือนก่อน +4

    Interesting that the series with this lambda is somehow derived from string theory. Why didn't you talk about how they discovered this series? Just writing down different series that converge faster or slower without any explanation is honestly pointless.

  • @deplorablebob4237
    @deplorablebob4237 หลายเดือนก่อน +2

    "There's a few things we're probably going to have to explain"
    Understatement of the day

  • @ig2d
    @ig2d หลายเดือนก่อน +3

    Did you know that the volume of a pizza radius "z", thickness "a" equals pi.z.z.a

  • @CyrilReinhardt
    @CyrilReinhardt 5 วันที่ผ่านมา

    This strategy is bomb!!! I won 3/4 just testing it out!!! Thank you for sharing!!

  • @nelsonjoppi
    @nelsonjoppi หลายเดือนก่อน +3

    7:37 that's the most mathematical conversation i've ever seem

  • @balijosu
    @balijosu หลายเดือนก่อน

    The amount of computing time the calculation takes is much more interesting than the number of terms. You can make a slow series converge faster by combining terms.

  • @Qermaq
    @Qermaq หลายเดือนก่อน +3

    What perplexes me is how these series have such arbitrary-looking integers in them. How the heck do you find these integers?

  • @aepokkvulpex
    @aepokkvulpex หลายเดือนก่อน +1

    If I'm not mistaken, Ramanujan said his was revealed to him in a dream

  • @burnere633
    @burnere633 หลายเดือนก่อน +6

    "...two Indian string theorists..." \*proceeds to pronounce Sinha as if it was Brazilian Portuguese\*

  • @doublepinger
    @doublepinger หลายเดือนก่อน

    I think it'd be interesting to compare the various approximations in a computational sense. Like ripple-carry vs look-ahead, or certain matrix formulations which at first glance change an Order of an algorithm - but then you find you're doing more per step, or need more memory. I bet there would probably be some "constant" or even "constants" where you can relate some measure of computational complexity per step, accuracy/deviation, and "family", where a "family" of solutions are more-or-less the same, more effectively separating the concept of effectiveness.
    Edit: I'm curious in the String Theorists derivation. First thought is 'wait Pi can be termed as the length of a "line" intersecting all the points at the same distance in a curved space' or a different geometric interpretation. There might be a similarity to how we have no equation for the perimeter of an ellipse. Just take it to extremes: an ellipse has 2-3 values: separation of centers and r, points and r, etc , but can we do MORE? Can we *require* two independent values e.g. they're not simplifiable, but both can take any value and produce pi?

  • @secretshrek
    @secretshrek หลายเดือนก่อน +4

    Why thumbnail is Indian pi

    • @purpleapple4052
      @purpleapple4052 หลายเดือนก่อน +7

      Because the guys who discovered the new series are Indian

    • @WAMTAT
      @WAMTAT หลายเดือนก่อน +5

      Because the people who discovered the new formula were from India

    • @numberphile
      @numberphile  หลายเดือนก่อน +9

      In fact 3 of the 4 formula we discuss, including the new one, were discovered by Indian mathematicians/scientists.
      An interview with the latest ones can be found at: th-cam.com/video/2lvTjEZ-bbw/w-d-xo.html

    • @secretshrek
      @secretshrek หลายเดือนก่อน +1

      Oh thanks

  • @hellfishii
    @hellfishii หลายเดือนก่อน +2

    We got new pi before GTA VI 😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭

  • @binbots
    @binbots หลายเดือนก่อน +5

    Wouldn’t there be an infinite amount of ways to represent pi? Math is just counting an infinite amount of zeros.

    • @noahblack914
      @noahblack914 หลายเดือนก่อน +8

      Of course there are. The one presented here also is itself an infinite number of ways to represent pi. But not all of those infinite representations are useful.

  • @tsaqifrizky5276
    @tsaqifrizky5276 หลายเดือนก่อน +1

    I may be missing something, but how does a 100 trillion digits of pi get confirmed? We don't know what "pi" is exactly (its transcendent so that makes sense) but we have confidently gotten to 100 trillion digits. How do we prove and confirm that in mathematics?

  • @bobh6728
    @bobh6728 หลายเดือนก่อน +1

    When you wrote the first series on paper, where you stopped could have been using odd numbers or primes for the denominators.

  • @nias2631
    @nias2631 หลายเดือนก่อน

    Great effort by these theorists! I like the precision of their statements.

  • @SeanForeman
    @SeanForeman 21 ชั่วโมงที่ผ่านมา

    From a 10,000ft perspective, It looks like the chudnovsky series is embedding static information about pi into itself to improve its accuracy. My guess is that we could increase the size of the static values within a new series to speed up the calculation.

  • @titleloanman
    @titleloanman หลายเดือนก่อน +1

    If you need a special formula to calculate accuracy to 105 trillion digits, how do you know when you hit the first wrong digit? And if you’re using something else to check the special formula, why do you need that formula in the first place?

  • @kavehtehrani
    @kavehtehrani หลายเดือนก่อน +1

    It's insane how they even came up with these series!

  • @peaceridge
    @peaceridge หลายเดือนก่อน +1

    In 1972, working on my Masters, I used a computer running on punch cards to calculate pi as far as it was able, so this video is very near to my heart. I'm amazed at the tiny laptop you are using - mind giving me the brand?

    • @SergioGomez-qe3kn
      @SergioGomez-qe3kn หลายเดือนก่อน

      I don’t know about the computer’s brand but I am almost sure that the program is Maple in case you were wondering. Best.

    • @peaceridge
      @peaceridge หลายเดือนก่อน +1

      @@SergioGomez-qe3kn Thanks, yes that's the program.

  • @BenSewell-qw6uk
    @BenSewell-qw6uk หลายเดือนก่อน

    R÷(e^(1÷π)-(1÷√2÷√3÷³√2÷³√3))= the radian along the surface of the sphere at two points where this will equal the strait line between them. It's a irrational number. It produces the length of the edge of the equal lateral triangle of the 20 sided 5th platonic solid where each of the points are equally apart from each other and at the radiuses distance to the surface. e is Euler's number and R is the Radius length.

  • @benjaminnewman6772
    @benjaminnewman6772 หลายเดือนก่อน +1

    It feels weird to line the different series up to "compete" with each other by how fast they converge as measured in the number of terms, when some of the series' terms have much more internal complexity than others. Is there a comparison which takes the net complexity in terms of computational operations into account?
    It looks like one term of the Chudnovsky series has something like a dozen times more internal operations than one term of the Madhava series - which still leaves it as the clear winner, which is why it's what's actually used to calculate digits of pi further than we've done before. But it would be nice to have the scorecard take that into account.

  • @TheRuler89
    @TheRuler89 หลายเดือนก่อน +2

    Man, the dirt on the monitor triggers me hard. Apart from that, a great video

  • @cipaisone
    @cipaisone หลายเดือนก่อน +2

    The lambda dependency looks like some chemical bond vs distance graph

  • @knickohr01
    @knickohr01 หลายเดือนก่อน

    11:03 This graph implies that there are exactly four different lambda without any approximation error, which means that your could calculate pi exactly in just four terms. The only problem is oft course to get those lambdas, as they are most likely also irrational.

  • @MJFLOW1
    @MJFLOW1 หลายเดือนก่อน

    Question: For the last one it is said "This is the one is used now to calculate Pi to ....... decimals" But next it gives an error for 4 terms. Error with respect to what? It doesn't make sense if it is compared to more than 4 terms of the same formula. Of course, it will converge faster to "its own kind". Who decides and how which one is a better approximation ?

  • @scaredyfish
    @scaredyfish หลายเดือนก่อน +1

    So the ‘state of the art’ series has a lot of intermediate calculations, compared with then Madhava series. I presume the state of the art is still the best, since they use it for computation, but it would be interesting to compare convergence based on computation time, rather than by number of terms.

  • @demerion
    @demerion หลายเดือนก่อน +2

    How do you calculate new digits of pi using these series? Is there a way to predict how many digits will be correct? Because otherwise you'd have to compare your result to some common truth.

  • @JuhaKona
    @JuhaKona หลายเดือนก่อน

    you make the most complex subjects super relatable!

  • @avaraportti1873
    @avaraportti1873 หลายเดือนก่อน

    Pi-ist logic:
    >define the circle and all circle-related formulae using the radius
    >define circle constant using the radius*2

  • @rodrigoqteixeira
    @rodrigoqteixeira หลายเดือนก่อน +1

    13:45 "pi-oneers". Haha I see what you did there

  • @marklonergan3898
    @marklonergan3898 หลายเดือนก่อน +1

    And thus, Quantumphile channel was born!

  • @ffs55
    @ffs55 หลายเดือนก่อน

    Amazing ep! Love y'alls support on this!

  • @347573
    @347573 หลายเดือนก่อน +1

    5:36 is unfair to compare like this the two methods... you should count the number of operations involved (and for example I think that factorial of n is counting as n-1 operations)...

  • @MichaelKingsfordGray
    @MichaelKingsfordGray หลายเดือนก่อน +1

    Pi is 1, when calculated in base pi.

  • @matthewmcdaid7962
    @matthewmcdaid7962 หลายเดือนก่อน

    For most practical purposes the approximation of the inverse of pi that is easiest to deal with is 113/355. It is elegant, and easy to remember. And ordinary folk aren't looking for the kind of accuracy that these complicated formulae are capable of giving after a half dozen or a dozen iterations. And it is accurate to within 8.5 millionths of a percent. And I cannot imagine taking the value generated by their formulae for the inverse of pi and calculating pi from it. For my approximation you invert the basic formula. End of story.

  • @deffunc
    @deffunc หลายเดือนก่อน

    Comparing number of terms is not fair: one should compare the number of operations. The series that require fewer terms have much more complicated expressions per term which contain many more operations.