Ramanujan: Making sense of 1+2+3+... = -1/12 and Co.

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  • Опубликовано: 1 окт 2024
  • The Mathologer sets out to make sense of 1+2+3+ ... = -1/12 and some of those other notorious, crazy-looking infinite sum identities. The starting point for this video is the famous letter that led to the discovery of self-taught mathematical genius Srinivasa Ramanujan in 1913 (Ramanujan is the subject of the movie "The man who knew infinity" that just started showing in cinemas.) Find out about how these identities come up in Ramanujan's work, the role of "just do it" in math, the rules for adding infinite sums on Earth and other worlds, and what all this has to do with the mathematical super star the Riemann Zeta function.
    You can download the jpeg of Ramanujan's letter to Hardy that I put together for this video here: www.qedcat.com/...
    (quite large)
    You can access a scanned copy of Ramanujan's notebook here: www.imsc.res.in...
    or check this out
    books.google.c...
    If you want to watch some other videos that deal with these strange identities I recommend the following:
    • Why -1/12 is a gold nu... (a Numberphile video featuring the mathematician Edward Frenkel who is also talking about the connection between the Riemann Zeta function and Ramanujan's crazy identity.)
    • Ramanujan Summation (James Grime's video (singingbanana & Numberphile) which aims at making sense of the formula at the heart of Ramanujan summation which I only flash briefly in the last part of the video.)
    • What does it feel like... (a very nice 3Blue1Brown video that makes sense of the identity 1+2+4+8+ ... = -1 in a way that is totally different from the one I am talking about in this video.)
    This week’s video is in response to a large number of you and my students at university asking me for my take on the whole 1+2+3+... =-1/12 business. Initially, the plan was to come up with one of my usual 15 minute long videos. However, after several unsuccessful attempts at not exceeding the magic Mathologer time limit, I realised that any “short” video like this would just be a clone of one of those wrong/misleading accounts of this topic that RUclips is full of. So, rather than just give up completely on this project I decided to do what you should never do if you actually want people to watch your videos, namely simply go for it and not look at the clock. The result - a video that is an insane 35 minutes long in which I say all the things that I think need to be said and can be said only using elementary math to (just barely) do this amazing topic justice.
    Thank you very much to Danil Dmitriev the official Mathologer translator for Russian for his subtitles.
    Enjoy!
    P.S.: If you know calculus and want to read up on all this some more, beyond what is readily available via the relevant Wiki pages and other internet resources, I recommend you read the last chapter of the book by Konrad Knopp, Theory and applications of infinite series, Dover books, 1990 (actually if you know German, read the extended version of this chapter in the original 1924 edition of the book). People usually recommend Hardy's book, Divergent series, but I'd say only look at this after you've looked at Knopp's book which I find a lot more accessible. The Hardy who wrote this book is the Hardy who I mention at the beginning of the video! Having said that, Hardy's book does have quite a bit of detail on how Ramanujan summation applies to the Zeta function; see chapters 13.10. and 13.17.

Комментарии • 6 тыс.

  • @tahmidt
    @tahmidt 8 лет назад +8609

    Imagine this;
    A guy comes up to you and offers you $1 on day 1, $2 on day 2, $3 on day 3... all the way to $n on day n and he keeps doing this for the rest of eternity. You might think that he's giving you free money but a mathematician will quickly realize that he is trying to con you and steal a twelfth of a dollar.
    But now you know.

    • @ishwar8119
      @ishwar8119 8 лет назад +172

      +Tahmid Islam (Tanveer) Fine of $0.09Mathematician: That guy lost 2/3 of a cent because of this

    • @rasowa2958
      @rasowa2958 8 лет назад +190

      +Tahmid Islam (Tanveer) That's just what Federal Reserve and other central banks do.

    • @dixonbuttes
      @dixonbuttes 7 лет назад +273

      I know I'm 9 months late, but I wanted to let you know this is the best comment I've ever seen on youtube.

    • @ramirez9919
      @ramirez9919 7 лет назад +16

      Tah mid Tanveer, But why only 1/12 and why not any other figure

    • @vijayakrishna07
      @vijayakrishna07 7 лет назад +20

      Tahmid Tanveer nice comment

  • @kevnar
    @kevnar 3 года назад +2439

    An infinite number of mathematicians walk into a bar. The first guy orders a beer. The second guy orders half a beer. The third guy orders a quarter of a beer the fourth, an eighth. The bartender just pours two beers and says, "You guys need to know your limits."
    I finally get that joke. Thanks.

  • @rifkyalfarizy9945
    @rifkyalfarizy9945 8 лет назад +2776

    before i started watchibg mathologer i hate math and have bad grades
    after i found this channel, i love math, and still bad grades
    luv dis channel

  • @guillermoh.k.2967
    @guillermoh.k.2967 4 года назад +2027

    Remember: Ganesha knows when you stop paying attention...

  • @parinitachakma765
    @parinitachakma765 5 лет назад +2488

    A simple stack overflow bug. God will patch it in the next update.

    • @capwilder2504
      @capwilder2504 4 года назад +17

      Skylark Phoenix 😂😂😂😂

    • @rohitupadhyay1116
      @rohitupadhyay1116 4 года назад +37

      There is no bug under his rule my friend

    • @andrewzhang8512
      @andrewzhang8512 4 года назад +36

      'stack overflow'. EVERY PROGRAMMERS LOVE!!!!

    • @wliaputs
      @wliaputs 4 года назад +30

      Rohit Upadhyay but i see bugs everyday

    • @rohitupadhyay1116
      @rohitupadhyay1116 4 года назад +11

      @@wliaputs 🤣🤣

  • @binayakthakur5122
    @binayakthakur5122 6 лет назад +1855

    It is like the software running the universe got overwhelmed and gave error - 1/12 Integer Overflow

    • @waywardson4472
      @waywardson4472 5 лет назад +34

      Binayak Thakur I was thinking along similar lines when he had all powers of 2 summed up to -1

    • @thesunexpress
      @thesunexpress 4 года назад +26

      Actually probably the Universe spat out "Cannot compute! Error: 1/137 "

    • @bee_irl
      @bee_irl 4 года назад +42

      -1/12, my favourite integer

    • @aklipsigman3451
      @aklipsigman3451 4 года назад +15

      It's real number not integer

    • @vivanmakwana2253
      @vivanmakwana2253 4 года назад +7

      it is not error it is a smarter idea of an indian and i am proud to be an indian

  • @Nero-ox5tw
    @Nero-ox5tw 4 года назад +1731

    This is why RUclips is leagues better than Facebook, Instagram, Snapchat, etc.

    • @drbhaviify
      @drbhaviify 4 года назад +30

      Yes agree

    • @ign_angry
      @ign_angry 4 года назад +13

      i use all

    • @Subs1338
      @Subs1338 4 года назад +6

      Why?

    • @thatkindcoder7510
      @thatkindcoder7510 3 года назад +90

      @@Subs1338 Because RUclips mainly teaches the objective truth, while other social media sites degrade your brain with attractive but biased false facts.

    • @dr.palsonp.h.d815
      @dr.palsonp.h.d815 3 года назад +51

      @@thatkindcoder7510 "objective" "youtube" HAHAHAHAHAHAHAHAH

  • @kevintan9483
    @kevintan9483 4 года назад +601

    Every time I make a mistake on a maths paper, I'm going to hear that sound and be scolded and scared out of my skin by Ganesha descending from the ceiling.

    • @pranavchandrav6071
      @pranavchandrav6071 2 года назад +5

      Jumpscare

    • @yedosti3092
      @yedosti3092 2 года назад +6

      This comment made me jump out of my bed laughing😂😂. Truly insane😂😂

  • @marksmod
    @marksmod 8 лет назад +929

    The elephant god of jump scares (aka. purple heart attack)

    • @McRaylie
      @McRaylie 8 лет назад +7

      +marksmod Ganesh?

    • @SomeoneCommenting
      @SomeoneCommenting 8 лет назад +37

      +McRaylie He means that every time that it appears the sound is VERY ANNOYING. I was using headphones when I was watching this video and it is a very unpleasant sound that makes you jump because it is unexpected and awkward.

    • @QuantumConundrum
      @QuantumConundrum 8 лет назад +21

      +marksmod Ganesh is secretly trying to murder all the mathematicians.

    • @Hect0rxP
      @Hect0rxP 8 лет назад +5

      hahahahaha all this comments have made me laugh so hard!!! hahahaha and yeah! freaking Ganesh! my heart almost stops >_

    • @shepaustad558
      @shepaustad558 8 лет назад +12

      Be kind

  • @PickyMcCritical
    @PickyMcCritical 7 лет назад +1811

    List of jumpscares:
    4:02
    9:28
    11:53
    22:50
    30:12
    31:57
    34:14

    • @ankitaaarya
      @ankitaaarya 6 лет назад +31

      PickyMcCritical 😂😂😂😂

    • @ekap1916
      @ekap1916 6 лет назад +14

      PickyMcCritical You ignorant knob!!

    • @biscuitsalive
      @biscuitsalive 6 лет назад +19

      PickyMcCritical terrifying

    • @vaishnavplays203
      @vaishnavplays203 6 лет назад +4

      Lol

    • @Akshaylive
      @Akshaylive 5 лет назад +51

      Thanks muck. This helped me prep.

  • @NoobMasterX1
    @NoobMasterX1 6 лет назад +1184

    Don't wear headphone when watching this video,
    have a nice day

  • @aadityasingh5575
    @aadityasingh5575 3 года назад +391

    I love how whenever Ganesha comes up we get a death threat

  • @donmoore7785
    @donmoore7785 4 года назад +830

    I like how Ramanujan left out his bold assumptions, but the recipient of the letter knew exactly what he meant.

    • @maxwellsequation4887
      @maxwellsequation4887 3 года назад +80

      Recipient was Hardy tho...

    • @abhaynatoo
      @abhaynatoo 3 года назад +115

      it was THE ramanujan talking to THE hardy. no commoners here. so its understandable.

    • @vaibhavkrupakar240
      @vaibhavkrupakar240 2 года назад +8

      Not an assumption, he proved it himself

    • @Alkis05
      @Alkis05 2 года назад +36

      It wasn't an assumption. If you pause the video, he says that he explain further in what conditions those divergent equations make sense. Most pointedly, he understood they were divergent and he made it clear he was not talking about standard summations.

    • @stevethea5250
      @stevethea5250 2 года назад

      @@Alkis05 timestamp?

  • @samtgamee3202
    @samtgamee3202 4 года назад +261

    thanks to Ganesha I will never forget infinity can't be subtracted from itself.

    • @gulshansharma2131
      @gulshansharma2131 3 года назад +5

      Why u can't subtract infinity from infinity ? Becoz u can't think up to infinity? Or u can't make sense about infinity ? Or u want to just follow others' work?

    • @gulshansharma2131
      @gulshansharma2131 3 года назад

      @Sam please elaborate a little bit😀

    • @rishisingh1035
      @rishisingh1035 3 года назад +9

      @@gulshansharma2131 u can't subtract infinity from infinity , but u can subtract 2 numbers tending to infinity and get 0

    • @beastgamer4932
      @beastgamer4932 3 года назад +1

      @@rishisingh1035 we’re not talking about limits here ok?

    • @rishisingh1035
      @rishisingh1035 3 года назад +10

      @@beastgamer4932 then u cannot subtract infinity from infinity

  • @WolfPack-gi7br
    @WolfPack-gi7br 6 лет назад +544

    4:02 that scared the hell out of me lol

    • @darkdelphin834
      @darkdelphin834 4 года назад +1

      Same here xd

    • @himanv
      @himanv 4 года назад +37

      Ganesh is the remover of obstacles and the lord of knowledge and light-- so yeah, makes sense he would scare the literal hell out of you! lol

    • @sarojnayak8350
      @sarojnayak8350 4 года назад +1

      @@himanv the sound was scary

    • @franklee8032
      @franklee8032 4 года назад +3

      And he never answers the question posed.. what's the point of even showing it?

    • @jacksummer4041
      @jacksummer4041 4 года назад +10

      I'm watching at 3am 😂 and i almost died

  • @sjegannath6295
    @sjegannath6295 Год назад +94

    It's important to note that this doesn't mean that the sum of all natural numbers is -1/12 but rather it's the solution to the riemann zeta function where this series occurs.

  • @Mathologer
    @Mathologer  8 лет назад +823

    This week’s video is in response to a large number of you and my students at university asking me for my take on the whole 1+2+3+... =-1/12 business. Initially, the plan was to come up with one of my usual 15 minute long videos. However, after several unsuccessful attempts at not exceeding the magic Mathologer time limit, I realised that any “short” video like this would just be a clone of one of those wrong/misleading accounts of this topic that RUclips is full of. So, rather than just give up completely on this project I decided to do what you should never do if you actually want people to watch your videos, namely simply go for it and not look at the clock. The result - a video that is an insane 35 minutes long in which I say all the things that I think need to be said and can be said only using elementary math to (just barely) do this amazing topic justice.

    • @MK-13337
      @MK-13337 8 лет назад +7

      I just finished watching this because I'm a time traveller. Great video!

    • @wkwmenen
      @wkwmenen 8 лет назад +27

      Jesus, that Indian God works as almost a screamer

    • @icefreezer7
      @icefreezer7 8 лет назад +1

      +Hououin Kyouma lol. me too. and nice name

    • @Mathologer
      @Mathologer  8 лет назад +12

      +Matti Kauppinen Fill me in on the secret of time travelling sometime. Would make for a great video I am sure :)

    • @Mindsway
      @Mindsway 8 лет назад +3

      great video ! the cesaro methode is cool :) But can we.. take the average of the average of the average... and so on to the infinite ?

  • @Kevbotomy
    @Kevbotomy 7 лет назад +667

    On a scale of 1 to -1/12, how would you rate this convergent series?

  • @yashjobanputra3832
    @yashjobanputra3832 3 года назад +103

    When he pauses for Hardy and then said "He is not dummy either", lol

  • @techsandbulls1869
    @techsandbulls1869 3 года назад +124

    man who knew infinity
    now i understand why the title of his biography makes sense

  • @andreguimaraes9347
    @andreguimaraes9347 8 лет назад +99

    The loud noise of the elephant thing coming up scares the crap outta me every time xD

  • @kcwidman
    @kcwidman 7 лет назад +905

    Oh my freaking goodness, I jumped right out of my seat with my headphones in at 4:00.

  • @villagelog1966
    @villagelog1966 4 года назад +834

    Ramanujan’s work in pure mathematics is now being used in engineering too. “In 1918, Srinivasa Ramanujan introduced a summation, known today as the Ramanujan-sum. He used this to express several arithmetic functions in the form of infinite series. For many years, this sum was used by other mathematicians to prove important results in number theory. In recent years, engineers and physicists have found applications of this sum in digital signal processing, especially in identifying periodic components of signals with integer periods,”

    • @rustalisin8950
      @rustalisin8950 4 года назад +3

      Pls Help ..Any Polynomial may be completely determined by a part of it. Analytic function is uniquely determined by a small part ( sample ) of it. OK. How can a Eta / Zeta Analyt function be used to extract binary modulation from a high density set of timespaced sloping carriers (let all carriers be linear, thus parallel, with guard band) I can see this series extracting (defined) harmonic modulation using array summation to yield an entire constellation across a message timespan of say 12milliSec. given 512 symnbols in 12mS.

    • @RecliningFurniture
      @RecliningFurniture 4 года назад +9

      Great, but what on Earth does all that mean? It is really not difficult to see why 1+2+3...etc does NOT equal -1/12 [but, incidentally, that 0.999...(0.9 recurring) DOES equal 1 (which I mention only to show that I don't have an issue with infinite numbers in calculations, where the calculations are actually grounded in logic)] . As that is so (and all you really need to know is that a series of plus numbers added together cannot logically equal a minus number unless you introduce a minus figure into your calculation, in which case it is no longer a series of plus numbers) I am not sure where that leaves the 1+2+3....series in terms of any practical application. Can anyone enlighten me on this, please?

    • @achyuththouta6957
      @achyuththouta6957 4 года назад +42

      @@RecliningFurniture 1+2+3+4..... is indeed equal to -1/12 although the explanation given by Ramanujan is completely wrong but this is used in string theory and has merit. Ramanujan gave insane explanations to this theorems and equations but most of them are correct

    • @RecliningFurniture
      @RecliningFurniture 4 года назад +14

      @@achyuththouta6957 Have to say I'm surprised people are still taking the whole -1/2 thing seriously. Mathologer has done another video about this (I'm not sure if it was before or after this one) where he completely debunks it. I don't know which proof you favour; the one I followed introduced plus and minus 1s and tried to make out these implied an average, when this was very obviously a completely different sequence - a mathematical sleight of hand. But, for the sake of argument, I would be interested to know where the logical fault lies in positing that adding only positive numbers to positive numbers must result in a positive number and cannot result in a negative one. I cannot personally fault the logic in that, but, as I say if the -1/2 sum is correct, there HAS to be a logical flaw in what I just said. Can you identify what it is, please? I would be extremely impressed (enlightened, even, in the truest sense) if you can.

    • @RecliningFurniture
      @RecliningFurniture 4 года назад +4

      @jamesk479 Thanks for this. You will need a specific rule to assign a solution to sqrt (-2). Such a rule would not accord with any maths I know, but that's OK, because it would be a rule specifically dealing with minus numbers, and the point of the rule I referred to above is that it deals only with positive numbers. To test the validity of the c = 1+2+3....etc here it should help to first consider a much simpler sum. So let's look at c* = 1+2+3 (which seems as reasonable a sum to consider as anything not containing an infinite series). So, c in this case equals 1+2+3. Which equals 6. Now, going on to use Ramanujan's methodology, we multiply by this 4 and subtract the x4 number from the original number. According to the demonstration in this video, this should result in -3c = 1-2 +3. But it doesn't. What we actually get is -3c = -3-6-9 (which is -18, so c =6, as we already knew).
      The practice of missing out every other number in the demonstration when multiplying by 4, and then including numbers missed out when subtracting the bottom number from the top, is going to give a bogus result. What we can actually say about the 'c' in = 1+2+3....etc is that c must >6, because the infinite series following 3 contains only additional positive numbers. Similarly, we can say with absolute confidence that c >10, because we know the next number in the sequence is a 4, and 1+2+3+4 =10, and there are more positive numbers to follow (an infinite number of them). Taking into account the number after that, we have 1+2+3+4+5 = 15, so c must be greater than 15. And so on. Forever. It turns out there are an infinite number of things we can say about c. We know exactly what types of things they are, and none of them are that c is equal to - 1/12.
      *c here obviously does not stand for the constant in an infinite series as Ramanujan used it, it is just c.

  • @aniketthakor
    @aniketthakor 4 года назад +179

    Happy Ganesh Chaturthi :)
    Love and respect form India

  • @slappy8941
    @slappy8941 5 лет назад +387

    LOL I like the shirt; "JUST OVER DO IT". This describes the German approach to engineering.

    • @Mal-Function4
      @Mal-Function4 4 года назад +9

      we aren't that crazy... look at the russian uragaan-class guard ships... THEY overdid it on the weight distribution

    • @gladtobeangry
      @gladtobeangry 3 года назад +10

      True. I used to live close to the german border near Aachen. I remember walking through a park there one time and thinking to myself "what are all these bulky stone monoliths lining the paths?". So I checked. Turns out that it were little lamp posts. If a dutchman had built those lamp posts, they'd have been made out of plexiglass, be covered in birdshit after day one, and be kicked into pieces by vandals after day two, after which we'd decide the park probably doesn't need lights. In Germany, they'll still be attached to the debris of earth when we get finally sucked into the supermassive blackhole.

    • @marlobardo4274
      @marlobardo4274 3 года назад +3

      @@gladtobeangry love your comment about German Massivbauweise

    • @iaroslavakornach
      @iaroslavakornach 3 года назад

      hahah just noticed it! I want that t-shirt now

    • @srinathtankasala
      @srinathtankasala 3 года назад

      @@iaroslavakornach did you find it? could you send me a link to buy?

  • @heyitsalex99
    @heyitsalex99 8 лет назад +71

    i havent watched the video yet, but thankyou for 3 reasons, 1. ramanujan 2. infinite sum of natural numbers 3. 30 minutes

    • @Mathologer
      @Mathologer  8 лет назад +27

      +heyits- alex Well, if you like Ramanujan, I'll probably do at least two more videos this year featuring his math :)

    • @heyitsalex99
      @heyitsalex99 8 лет назад

      +Mathologer yassss

    • @Mathologer
      @Mathologer  8 лет назад +12

      +Appleguysfriend A video on Galois theory would be nice (probably a 60 minute one though :)

    • @funcaogamma7663
      @funcaogamma7663 8 лет назад

      +Mathologer yes

    • @4Pssf2w
      @4Pssf2w 8 лет назад

      +Mathologer yes

  • @HeinrichTsanov
    @HeinrichTsanov 8 лет назад +794

    The elephant god jumpscared me for many times...

    • @KL-sq9hg
      @KL-sq9hg 8 лет назад +64

      his name is lord ganesha well dont say like he is bad i and many more than a billion people around the world worship him

    • @ullqiorracifer9935
      @ullqiorracifer9935 8 лет назад +16

      +Firicious Gaming- Clash Royale and More i dont think everyone in india is a hindu

    • @nalawade
      @nalawade 8 лет назад +26

      around 80 % are

    • @KL-sq9hg
      @KL-sq9hg 8 лет назад +13

      ***** well i said around the world just google it

    • @autodidactusplaysjrpgs7614
      @autodidactusplaysjrpgs7614 8 лет назад +1

      Stimulus and response

  • @felipelopes3171
    @felipelopes3171 4 года назад +233

    I think Ramanujan was quite aware of what his sum meant. He mentions it's the "center of balance" of the series. You can get the -1/12 value using the Euler-Maclaurin formula with an expansion around 1/n -> 0. This is a pretty novel way to interpret the value of the zeta function.
    Anyway, about this confusing people in calculus, I think people learn much more math by analyzing where the -1/12 comes from than when they dismiss the formula.

    • @akanksha8311
      @akanksha8311 2 года назад +3

      well said

    • @Entropy3ko
      @Entropy3ko Год назад +10

      The problem is that people do not understand how limits work, often
      Functions like F(x)= Sin(x)/x has a limit equal to 1 at x-->0, but the function itself does not exit at 0.
      So you can pin a value to F(0), but this does not mean the function at that point actually exists.

    • @Wallofdenial50
      @Wallofdenial50 Год назад

      Kind of a divide by zero accident

    • @abhishankpaul
      @abhishankpaul 11 месяцев назад +2

      ​@@Entropy3ko people conveniently skip the word "approach" when studying limits and then complain when shit blows up

  • @RamirodeSouza
    @RamirodeSouza 8 лет назад +57

    *WARNING*: Ganesha will scare the shit out of you.

  • @Hecatonicosachoron
    @Hecatonicosachoron 8 лет назад +254

    Those interjections by Ganesha are terrifying

    • @xendu-d9v
      @xendu-d9v 3 года назад +6

      Jay shri Ganesh

    • @HinduWarriorForever
      @HinduWarriorForever 2 года назад +2

      "You are encapsulated by evil energies. Pray to Bhagwan Narsimha. Stay calm. Respect fellow people. Don't get into alcoholism.*

  • @MemberHomei
    @MemberHomei 8 лет назад +454

    I get a shock each time the elephant god appears! You should have toned it down a bit

    • @bonbonpony
      @bonbonpony 8 лет назад +49

      +MemberHomei One does not simply tone down a goddamn Elephant God :P

    • @keyar87
      @keyar87 8 лет назад

      +Bon Bon Hahaha :P

    • @StrategicGamesEtc
      @StrategicGamesEtc 8 лет назад

      +Bon Bon What about a bugbear? :D

    • @bonbonpony
      @bonbonpony 8 лет назад +1

      StrategicGamesEtc What about him? The mead tasted good ;J

    • @bonbonpony
      @bonbonpony 8 лет назад

      Bhaswar Roy Ki?

  • @adityanair7159
    @adityanair7159 3 года назад +35

    Jai shree Ganesha Cutest God 🙏😇
    The God of Wisdom .

    • @xendu-d9v
      @xendu-d9v 3 года назад +7

      Jay shri Ganesh

    • @catwithsunglasses3949
      @catwithsunglasses3949 3 года назад +10

      @@KhvLeD yea what’s wrong with that? I’m an atheist but even I don’t think anything is wrong with believing in multiple gods lmao.

    • @sttpt9217
      @sttpt9217 3 года назад +2

      @Store Patternator 😂 lol we don't belive in man made religion like Islamism, Christianity ..

    • @superman5742
      @superman5742 3 года назад +1

      @Store Patternator nothing...just carry on with our respective lives 😂

  • @Eric06410
    @Eric06410 7 лет назад +224

    He does this to show off his t-shirt collection

    • @Mathologer
      @Mathologer  7 лет назад +53

      There are easier ways to show off ones t-shirt collection :)

    • @gourabdas8560
      @gourabdas8560 5 лет назад +1

      😂😂😂

    • @wolframalpha8634
      @wolframalpha8634 5 лет назад +1

      😂😂😂

    • @bharthyadav6794
      @bharthyadav6794 5 лет назад

      Lol

    • @sillybears4673
      @sillybears4673 5 лет назад +2

      He is laughed at this comment because all his shirts are awesome and related to the videos usually lol

  • @paulczar
    @paulczar 6 лет назад +401

    If this guy had been by math teacher is high school, I’d probably be a mathematician by now. Amazing what a good, passionate teacher can do for you.

    • @jacksummer4041
      @jacksummer4041 4 года назад +14

      😂 yeah a mathematician who's trying hard to find contradictions to proof that originally do not have any contradiction

    • @angelc9818
      @angelc9818 3 года назад +8

      he has been my teacher

    • @DocBree13
      @DocBree13 2 года назад +1

      I feel the same

    • @ripjawsquad
      @ripjawsquad 2 года назад +7

      @@jacksummer4041 isn't that what good mathematicians do

    • @AlexanderSuraphel
      @AlexanderSuraphel 2 года назад

      @@angelc9818 I've read someone commenting the same. Which school was it?

  • @HariPrasadindependantphysicist
    @HariPrasadindependantphysicist 8 лет назад +113

    For anyone who wants to know what is the number shown in his shirt (from 16:53 to 26:09), its the expansion of *pi* in base 3 = 10.01021101222201.........

  • @jaimeriveras
    @jaimeriveras 3 года назад +58

    As in the case of quantum mechanics, I understand very little, but it’s enough to appreciate the beauty of it all. Amazing stuff.

  • @philippedavid0
    @philippedavid0 8 лет назад +39

    Great video, but man you made me jumpscare with those " *BOOM* Elephant speech bubbles" !

    • @mtomazza
      @mtomazza 8 лет назад

      +Philippe David me too

  • @pierineri
    @pierineri 8 лет назад +57

    Of course, green aliens have three fingers, that's why they use base 3 ;)

  • @PaulKruskamp
    @PaulKruskamp 8 лет назад +154

    I did the maths and came up with 42.

    • @JakeIsEpicHavard
      @JakeIsEpicHavard 8 лет назад

      😐

    • @PaulKruskamp
      @PaulKruskamp 8 лет назад

      EpicGuyRandom you don't get it.

    • @JakeIsEpicHavard
      @JakeIsEpicHavard 8 лет назад +9

      +Dean Thorton no i do 😂 but that is the answer to everything ...

    • @PaulKruskamp
      @PaulKruskamp 8 лет назад +1

      EpicGuyRandom lol, so silly

    • @perryt2039
      @perryt2039 8 лет назад +9

      I did it and came up with 69.6969696969696969696969...

  • @TommyAmbersonRD
    @TommyAmbersonRD 4 года назад +91

    2:54 "keep it completely elementary" .
    My definition of elementary is clearly not the same as his.

  • @michaelwinter742
    @michaelwinter742 8 лет назад +113

    Interestingly, this video is the zeta function output of all the videos on RUclips being added together.

  • @jedus007
    @jedus007 5 лет назад +59

    Ramanujan was sheer poetry in Mathematics.

  • @sergiin3
    @sergiin3 4 года назад +69

    A man who knew infinity.
    Good book about Ramanujan's life.

  • @devjeetnanda7698
    @devjeetnanda7698 4 года назад +81

    The way lord Ganesha pops up with that sound.... It feels like he's giving some sort of mythological warning
    Edit: I forgot to mention while writing this comment that I was watching the video on Ganesh Chaturthi(weird YT algo right, for most Indians) and that my half yearly exams were a week away starting with MATHS as the first exam

  • @DaUsher
    @DaUsher 8 лет назад +380

    Therefore, 1 > 1+2+3+4+5+...

    • @chillphil967
      @chillphil967 8 лет назад +5

      You jerk! lol

    • @jimbean4751
      @jimbean4751 7 лет назад +41

      and that's why 0 isn't a natural number :)

    • @bradenweber3654
      @bradenweber3654 7 лет назад +36

      That's only using the Cesaro convergent, which deals with averages rather than sums. Such could make sense in the regular mathematical system of an alien planet, but we decided our system would be different. That doesn't stop mathematicians from find answers outside of our mathematical system though.

    • @fdagpigj
      @fdagpigj 7 лет назад +14

      Unless I misunderstood, the Cesaro convergent only deals with the averages which are still positive, it's the analytic continuation of the Riemann function that gives the sum a negative value.

    • @chizhang2765
      @chizhang2765 7 лет назад +4

      I find the use of word "alien" quite confusing. Isn't it just some sort of fun experiments with maths? Or do they describe actual physical realities in some way, that addition→finding converging point of average of partial sums would actually be useful in simplifying physical equations in certain cases? Please do tell me more. I would be really grateful.

  • @mylord6868
    @mylord6868 7 лет назад +71

    i am hindu and i am totally ok with Ganesh thing, and i am not going to Charlie hebdo office😀.
    btw nice explanation professor👍👍

    • @hank1519
      @hank1519 5 лет назад +1

      A little too soon for the joke, I fear.

    • @DharamG
      @DharamG 5 лет назад +1

      My lord, Who is asking you what you are? U can't give any certificate pretending to belong to a community

    • @BBCBullshit
      @BBCBullshit 5 лет назад +1

      @@deka0014 😂😂😂😂😂😂

    • @alvarogoenaga3965
      @alvarogoenaga3965 5 лет назад +1

      Cool. After all, all deities are probably and possibly products of some people's imaginations.

    • @alvarogoenaga3965
      @alvarogoenaga3965 5 лет назад

      @@wolfx1654 .What are you saying, heathen? No, not my deity. Mine is 100% real.
      J/K

  • @94D33M
    @94D33M 6 лет назад +250

    Next time when you get wrong in ur maths question, remember to tell your teacher about maths in another world, your answer is definitely right in atleast one planet in the universe

    • @wav372
      @wav372 4 года назад +15

      If universe is infinite then your answer is right on the infinite amount of planets

    • @shimpiyaa
      @shimpiyaa 4 года назад +6

      1 = 2 is right in our planet.
      Assume 1= 2
      1/0=2/0
      1×0=2×0
      0=0
      LHS and RHS are equal
      Hence proved.
      Infact any number is equal to any number.

    • @shoumikchakraborty3604
      @shoumikchakraborty3604 4 года назад +8

      @@shimpiyaa Adding one more proof
      d/dx (X ^2) = d/dx(x) + d/dx(x) +d/dx(x) ... x times ....+d/dx(x)
      2X= 1+1+...X times +1
      2X=X
      Dividing X both the sides
      2=1

    • @hamiltonianpathondodecahed5236
      @hamiltonianpathondodecahed5236 4 года назад +33

      the teacher would be like : then go on dat planet

    • @drbhaviify
      @drbhaviify 4 года назад +1

      @@hamiltonianpathondodecahed5236 correct 😅😂😂😂😂

  • @ralphallengamboa9394
    @ralphallengamboa9394 3 года назад +22

    This is much better than an intense film. That Elephant jump scares.. 😂

    • @MrDrgdf
      @MrDrgdf 3 года назад +12

      Hindu God Ganesh.

  • @DustinRodriguez1_0
    @DustinRodriguez1_0 8 лет назад +151

    If given access to a time machine, my first stop would be to visit Hardy when he firsts open and reads that letter from Ramanujan. I can't even imagine what the next few hours and days of his life must have been like. He probably thought he was losing his mind.

    • @Metalhammer1993
      @Metalhammer1993 7 лет назад +27

      Dustin Rodriguez nope he actually read it, showed it colleagues and set everything into motion Ramanujan got financial support and transport to England. Harvey was baffled someone with no formal training could deduce all that. but the content of the letter at best slightly surprised him. the shocker for Hardy was Ramanujans talent

    • @dscruiter
      @dscruiter 6 лет назад +16

      I would have made certain Ramanujan's health would be okay. Then we could have enjoyed his brilliance so much more and witness more math miracles.

    • @tsresc
      @tsresc 6 лет назад +4

      @Tangent of circle. Thanks for giving me the idea. 😉
      I'll teach him a few things in exchange of being my mathematician.

    • @zoetropo1
      @zoetropo1 5 лет назад +2

      Dustin Rodriguez: if given access to a time machine, your first stop would be the explosion when you turned it on. That’s what happens when a backward-going time machine occupies the same space-time as a forward-going one.

    • @chandrasinghrawat622
      @chandrasinghrawat622 5 лет назад +1

      Certainly

  • @gobstompper13
    @gobstompper13 8 лет назад +25

    Enjoy your channel. I'm sorry to point out that your elephant sound byte scares me.

  • @chrisdavis5698
    @chrisdavis5698 4 года назад +36

    who else was baffled by how breath-taking gorgeous that handwriting was?? jeez.

  • @rajendramisir3530
    @rajendramisir3530 2 года назад +16

    Srinavaasa Ramanujan said every equation was a prayer for him. Ever since I learned about him in my Calculus 2 class 30 years ago, he has been my Mathematics role model. He approximated the value of 1/Pi to a few decimal places using infinite series.
    Srinavaasa Ramanujan gave our world his gift of genius and departed peacefully from this material world. It feels sad to loose men of great minds like him.
    Although he was not a trained Mathematician, he was able to enlighten our world of Mathematics with his genius of Mathematical deductions and profound insights. I am impressed at how he caught the attention of Professor GH Hardy of Cambridge University by his(Ramanujan) letter of theorems on infinite series that diverge( 1+2+3+ ... = -1/12.

  • @dance1211rec
    @dance1211rec 8 лет назад +86

    christ sake the elephant keeps giving me a heart attack everytime he appears

    • @Mathologer
      @Mathologer  8 лет назад +20

      +dance1211 Well, it's a long video, so I thought I better have a wakeup call every once in a while :)

    • @AnstonMusic
      @AnstonMusic 8 лет назад +7

      +Mathologer
      Please, no more. I'm afraid of it popping up. :(

    • @Morgalucci
      @Morgalucci 8 лет назад

      I felt a cold shiver through my body into my feet when it first came up.

    • @pronounjow
      @pronounjow 8 лет назад

      +Mathologer It's actually taking me a lot longer to finish the video because I have to take a break to calm myself down every time the elephant shows up, and it's kind of hard to focus because I'm too scared of when the next one will pop up...
      It's also surprisingly hilarious in a twisted way XD !

    • @Asdfghj87
      @Asdfghj87 8 лет назад +1

      +dance1211 agree. @Mathologer: the elephant "boom" noise is way too loud. Thanks for the video though, awesome content as usual.

  • @jwinburn
    @jwinburn 5 лет назад +218

    Ramanujen once wrote just for fun
    that the sum of the numbers from one
    was not aleph naught
    as we might have all thought
    but one twelfth times negative one

    • @calebberhow2203
      @calebberhow2203 5 лет назад +11

      This is the best math poem I have ever read. (Haven't read many, but I had a laugh.)

    • @gaymerjerry
      @gaymerjerry 4 года назад

      aleph null isnt the sum of all the natural number aleph null is the total number of natural number

    • @petrie911
      @petrie911 4 года назад +3

      @@gaymerjerry In cardinal arithmetic, the sum of all natural numbers is indeed aleph null. In ordinal arithmetic, it's omega, which is equal to aleph null in the most common formulation of set theory.

    • @gaymerjerry
      @gaymerjerry 4 года назад +4

      @@petrie911 i dont think you know what cardinal and ordinal means if you said that
      cardinality literally mean sizeof or absolute value while ordinal means ordered lists
      you can have -omega but -aleph null is nonsense
      aleph null is the amount of counting numbers there are while omega is ordering them then adding another one at the end of the list (as adding another one at the beginning of the list still cant really make omega as ordinal infinity is communitive)

    • @gaymerjerry
      @gaymerjerry 4 года назад +1

      @@petrie911 and also its not called cardinal arithmetic "Cardinal numbers" are a generalization of the natural numbers to describe sets of infinite size in set theory thats it if you ever put on any math test that all natural numbers add to a cardinal number you will get 0 points because the act of adding number is ordinal numbers
      if you were saying you can combine 2 sets to get a larger set you can do that to prove 2 * aleph null = aleph null
      you have the set of {0,2,4,6,8,10,12,14,16,....} and {1,3,5,7,9,11,13,15,...} now according to standard axioms if a set is infinite but can still be made into an ordered list its size is aleph null set one is clearly listed where each term matched to 2x and set to each term matches to 2x+1 and the fact i could put a ... to imply more number further proves its an ordered list so combine these 2 sets of size aleph null creates {0,1,2,3,4,5,6.....} which is the natural numbers which is the set that aleph null is based on but can also map each term to x
      so combining these 2 sets we show 2 * aleph null = 0

  • @AaronBruffett
    @AaronBruffett 8 лет назад +17

    Mathematician Love poetry:
    How do I love Thee
    let me count the ways
    -1/12 ways

  • @zainulabideen5895
    @zainulabideen5895 3 года назад +93

    One Word for Ramanujan, "Genius of Genuis", He is a idol of motivation for math students, #Respect

  • @arnabpaulchoudhury8455
    @arnabpaulchoudhury8455 5 лет назад +56

    Lord Ganesha surely knows his stuff... :D

  • @oldcowbb
    @oldcowbb 8 лет назад +30

    the elephant god gives me heart attack

    • @metallsnubben
      @metallsnubben 8 лет назад +1

      +oldcowbb I was watching youtube before sleep here, and then that goddamn elephant kept showing up with perfect unexpected timing.
      Needless to say, I'm gonna be tired tomorrow... :(

    • @Mathologer
      @Mathologer  8 лет назад +10

      +oldcowbb Looks like you won't forget this video then. I'd say mission accomplished :)

  • @malzcuatro3379
    @malzcuatro3379 4 года назад +108

    Trying to understand the genius of Ramanujan. Four minutes into the video:
    "Well, Rananujan somehow sees that..."
    I guess not today...

    • @acvarthered
      @acvarthered 4 года назад +7

      Allow me to summarize. Even geniuses come up with dumb ideas.

    • @salvaalveal3848
      @salvaalveal3848 4 года назад +5

      Geniuses are always ridiculed for having "dumb ideas", just ask Cantor.

    • @RobBCactive
      @RobBCactive 3 года назад +1

      He showed the reason for that insight later in the video, where the series was convergent it's simple pattern matching but ignoring the validity conditions

    • @Artaxerxes.
      @Artaxerxes. 3 года назад +4

      @@acvarthered believe me. You're not intelligent enough to call it dumb. I will readily consider it if Grigori or Terrence Tao call it dumb. Just not you pal. Because there have been plenty of dumb people who ridiculed at geniuses

  • @ArigatoPlays
    @ArigatoPlays 4 года назад +31

    Man, I was really following the video understanding everything, being convinced at the end of this I'd understand the Riemann Zeta function only for you to hit me with that 32:27 lmao

  • @Maxaxik
    @Maxaxik 8 лет назад +15

    I'm afraid of elephants now

    • @asthbasagr9486
      @asthbasagr9486 8 лет назад

      +Bhaswar Roy bhai kyu gaali bak raha he? give him d knowldge.. maintain our peaceful legacy brother... peace

    • @bhaswarroy802
      @bhaswarroy802 8 лет назад

      may be you are right +asth basagr

    • @asthbasagr9486
      @asthbasagr9486 8 лет назад

      Bhaswar Roy thank u brother...cheers

  • @UltraRik
    @UltraRik 7 лет назад +20

    Thank you for teaching us the complex math of blue aliens

  • @jimmyalderson1639
    @jimmyalderson1639 8 лет назад +18

    It's hard enough learning this, just imagine how hard it was to solve in the first place

  • @augustjologs1
    @augustjologs1 4 месяца назад +3

    I watched all the way to the end, pretending to kind of understand the essence of what he is saying, without truly understaning it, just to say myself, 'hey, I reached the end, so I'm not a total schmuck afterall".

  • @MrPoutsesMple
    @MrPoutsesMple 8 лет назад +21

    It's amazing how complex analysis pops in...Really cool video. I enjoyed the visualizations, but the elephant God was a bit scary..

    • @MyAce8
      @MyAce8 8 лет назад +1

      +ΣΚΡΟΥΤΖ ΜΑΚ ΝΤΑΚ He came out of nowhere, I am going to have nightmares for weeks

    • @rcksnxc361
      @rcksnxc361 8 лет назад +1

      +Ace shinigami lolxd

    • @MyAce8
      @MyAce8 8 лет назад +4

      I guess it's more the sudden noise that accompanies him

  • @rajeshkoppa2367
    @rajeshkoppa2367 7 лет назад +95

    True knowledge comes from humblest of origin.....

    • @rosaliacastro1551
      @rosaliacastro1551 4 года назад +11

      Not necessarily.

    • @KodamatiUdayaPrabhuKiran
      @KodamatiUdayaPrabhuKiran 4 года назад +5

      @@rosaliacastro1551 necessarily

    • @jovian304
      @jovian304 4 года назад +3

      @@KodamatiUdayaPrabhuKiran not necessarily.

    • @KodamatiUdayaPrabhuKiran
      @KodamatiUdayaPrabhuKiran 4 года назад

      @@jovian304
      I guess your name says you are dumb and arrogant

    • @jovian304
      @jovian304 4 года назад +5

      @@KodamatiUdayaPrabhuKiran Well I know meaning of ur name is sunshine. There's nothing wrong in having name as "sunshine". Just don't judge others.

  • @RedAgent14
    @RedAgent14 6 лет назад +180

    4:05
    *head snaps up*
    me: I'm paying attention, I'm paying attention!
    *roommates give me a weird look*

    • @Mal-Function4
      @Mal-Function4 4 года назад +5

      Ganesh please don't hurt me.

    • @-PiyushJi
      @-PiyushJi 3 года назад

      @@Mal-Function4 he will not he is ❤️

  • @roughysk9851
    @roughysk9851 3 года назад +35

    Ramanujan was genuinely a masterpiece

  • @resonarc
    @resonarc 8 лет назад +63

    those elephants that pop up scare the crap out of me!

  • @nilavadebnath2425
    @nilavadebnath2425 6 лет назад +297

    The man was a genius (Ramanujan)

    • @zoetropo1
      @zoetropo1 5 лет назад +34

      NILAVA DEBNATH genius

    • @notme-ji5uo
      @notme-ji5uo 5 лет назад +3

      nope

    • @TheChzoronzon
      @TheChzoronzon 5 лет назад +8

      @@iampol9957 Anybody that thinks that cows, particularly, are sacred has serious problems

    • @shweatypalms4423
      @shweatypalms4423 5 лет назад +71

      @@TheChzoronzon and people that bring trees into their homes arent, weird people everywhere my guy. We all bleed red at the end of the day

    • @TheChzoronzon
      @TheChzoronzon 5 лет назад +1

      @@shweatypalms4423 Yeah, hippies are the worst...Cartman for president! No, wait

  • @smritidipa
    @smritidipa 4 года назад +53

    I think you should give a image of NAMAGIRI the Hindu goddess on whom "Ramanujam" ( actual name not Ramanujan) had faith.

    • @hello123s
      @hello123s 3 года назад +2

      @Adarsh Jha it is.. She is a feminazzi.. Who just wants credits for no reason..

    • @stuntxo3968
      @stuntxo3968 3 года назад

      Correct

    • @anshul6168
      @anshul6168 3 года назад +1

      He had faith over all Hindu Gods
      In Hinduism you can worship any god but that doesnot mean people who worship Devi dont have faith in Ganesha
      Ganesha is known as obstacle remover

    • @samchaco2
      @samchaco2 3 года назад +1

      Right? Its so poor research, he actually credits Goddress Namagiri for revelations. How easy would that have been to quote.

  • @JasonFuller
    @JasonFuller 5 лет назад +10

    20:30 Again, just labeling something "Cesaro convergent to 1/2" causes a loss of information that could very well be of theoretical importance later. Means are statistical tools that aren't all that useful without knowing at least the standard deviation. Shouldn't the amplitude (and possibly periodicity) of the oscillation also be tracked when reducing a series to a Cesaro number?

  • @slouch186
    @slouch186 8 лет назад +31

    the sound that plays when ganesh appears to say something keeps startling me

    • @khushnoodnaqvi3793
      @khushnoodnaqvi3793 8 лет назад +3

      +slouch Yes, OP. Pls remove the horrible ding sound.

    • @bonbonpony
      @bonbonpony 8 лет назад +8

      +slouch But it should! You should be scared when doing such an insanely wrong step in the Great Ganita*. The Elephant God is there to remind you of that.
      (*Ganita = Sanskrit word for Mathematics)

    • @pranavzarekar8369
      @pranavzarekar8369 7 лет назад +1

      roar falcon well that's not true

    • @pranavzarekar8369
      @pranavzarekar8369 7 лет назад +1

      the mathematics of ancient india and hindu mythology is actually related to is science , it's just that theories aren't been explained and we are still unable to understand coz it's too fuckin advance for us . the verse of an ancient book contains the distance to sun which was later later found out by scientist .

    • @bongo990
      @bongo990 7 лет назад +2

      Pranav Zarekar you are saying dumb shit here.

  • @smb123211
    @smb123211 5 лет назад +11

    There are several articles on the web explaining this trick. Scientific American (for example) noted the intellectual dishonesty of redefining terms without telling the reader. But the best (and funniest!) explanation is at Physics Buzz blog. it clearly shows that "-1/12" is an area obtained by graphing the integration of x(1+x) / 2. (This is the formula alluded to by SR)
    Raising x to a power (in the formula) gives various answers but what's interesting is that x to the 13th gives...-1/12 - the same as x to the 1. LOL

  • @crewrangergaming9582
    @crewrangergaming9582 Год назад +6

    Ramanujan was no doubt a god-send, whose mind formed in such a beautiful way that these came to him out of nowhere. It is spiritual, it came to him by itself, as if Universe conspired to make him aware of these nuances of maths in the Universe.

  • @Poor_Vampire
    @Poor_Vampire 5 лет назад +50

    I never knew Ramanujan was SUCH A GENIUS !
    Thanx to mathologer.

    • @u.v.s.5583
      @u.v.s.5583 4 года назад +6

      He actually could do much much more than this!
      But don't read this comment any further or you will regret it.
      Remember, I warned you. Stop reading this comment.
      Really.
      Ramanujan was such savage genius that he even caught in London Tbc instead of Covid.

    • @gumnaam4302
      @gumnaam4302 3 года назад

      @@u.v.s.5583 Exactly, the man who knew infinity catches TBC in the heart of the nation that looted and pillaged more than half the world and was still grappling with TBC!! So much for being a pomp regime. Such a shame!!

    • @shubhama891
      @shubhama891 3 года назад +4

      He actually wrote many formulas and assumptions in last year of his life. Researches are still going on. Many of his formulas are still used to find the black hole😲😲

  • @anj000
    @anj000 8 лет назад +5

    34 minutes really are not insane. Maybe only comparing to typical pop-science films on YT but why anyone should folow this rules for actual dummies who are bored watching 30 minutes long film. Do not be affraid of making longer films.
    And my second advice is try to make more charts/plots, its makes topic easier to understand and encourage people to watch.

  • @Horrortelltales
    @Horrortelltales 7 лет назад +239

    I'm too stupid to understand this.. peace out.

    • @yoshtg
      @yoshtg 6 лет назад +9

      nah, its a maths-meme and its not really funny imo.

    • @ashley2khoo510
      @ashley2khoo510 6 лет назад +5

      YoshTG its not a meme?

    • @jamesbeasley6661
      @jamesbeasley6661 6 лет назад

      SweDawgTv see

    • @btdpro752
      @btdpro752 6 лет назад +5

      SweDawgTv calling your self stupid makes you stupid. Having over confidence makes you stupid. Not trying any not preparing makes you stupid.

    • @WitchidWitchid
      @WitchidWitchid 6 лет назад +12

      If you are watching it then you're probably not too stupid to understand it. Perhaps you simply need to learn more background maths to understand this.

  • @vaibhavtiwari8865
    @vaibhavtiwari8865 3 года назад +56

    Remember Ramanujan don't have any formal education even after that He was a Genius ❤️

  • @Just_A_Dude
    @Just_A_Dude 8 лет назад +19

    Okay, so the Reimann Zeta thing shows me in a way I understand that Ramanujan isn't full of crap, but I still have something nagging at me that is way more basic than anything in the video: Why the hell is it okay for him to skip every other space when he's doing 4c=4+8+12 and subtracting it from c?

    • @coryman125
      @coryman125 8 лет назад +14

      I could be wrong, but I think it's because they're all being added together. For example, 1+2+3=6. If you subtract 2=2 from it, you get 1+3=4, but you can also get -1+2+3=4, or 1+2+1=4. It doesn't change the actual result, just the way it's displayed

    • @Just_A_Dude
      @Just_A_Dude 8 лет назад +4

      coryman125 That makes the most sense of anything I've heard yet.

    • @qzxerty
      @qzxerty 8 лет назад +2

      So he isn't skipping anything, he is doing the full sum. The way he puts like terms under one another is purely for convenience and clarity. One can think of this phenomenon as due to the fact that the two series are infinite. Hence, you get these interesting results when subtracting a multiple of an infinite series from itself.
      In case you find this shocking, this kind of subtraction is very common when dealing with convergent series and leads to both meaningful and mathematically satisfying answers. It is usually taught in the first year of any course in Calculus/Analysis (high school/first year uni) because of it's utility in calculating integrals, that is, calculating the area of the graph under the curve bounded by an x axis.
      If you are still having difficulty maybe do a little more study on infinite series (the nice, convergent kind) and then rewatch this video.
      I'm not a mathematician so the maths gurus can correct my errors in my explanation, Thanks.

    • @TejaswinG
      @TejaswinG 8 лет назад +6

      A number can be rearranged along with their signs in a series. Think of the spaces as adding zeros :)

    • @AlcyonEldara
      @AlcyonEldara 8 лет назад +7

      Well, you cannot rearrange the terms. Not always.
      In the "standard way", a semi-convergent serie can be "rearranged" to converge to every single real number or even be divergent. As a consequence, any summation method expanding the "standard way" has this issue.
      But now wa can talk about adding 0 in between. It seems to be ok, it works in the "standard way". For the "Cesaro way", you might check this
      1-1+1-1+1-1+....
      Now add a zero after each +1. You will get
      1+0-1+1+0-1+... the partial sums are
      1 1 0 1 1 0 1 1 0 .... and the averages are
      1 1 2/3 3/4 4/5 4/6 5/7 6/8 6/9 ... and this sequence converges to 2/3
      So, no, you cannot add spaces without problem :)

  • @HeavyboxesDIYMaster
    @HeavyboxesDIYMaster 8 лет назад +16

    Who else watched the whole video!

    • @parsley6942
      @parsley6942 8 лет назад

      +Heavyboxes I made it to understanding the intuition behind Cesàro summation.

    • @Mathologer
      @Mathologer  8 лет назад +27

      +Heavyboxes I watched the whole thing about twenty times :)

  • @garymartin9777
    @garymartin9777 Год назад +2

    the error is the residue term -- infinity -- cannot be subtracted from itself. It is an undefined operation like division by zero. so the method is invalid.

  • @DDF546D5F4
    @DDF546D5F4 6 лет назад +7

    I think it is similar with defining sin(-30°). We cant see an angle like -30° in triangle, but we use it because it is useful and continuous. I think 1+2+3... is similar with my example. We think it diverges, but if we define sum of series in other way, it is -1/12 and it is continous and useful.

  • @Bleubear3
    @Bleubear3 8 лет назад +6

    How did I even get here. Autoplay set me up. I gave it a go, I'm at 16:31 and I give up LOL
    "This makes zero sense to me."
    That's all I've been saying the past couple of minutes. I'll let you mathematicians be. You're doing us a great service.

    • @Mathologer
      @Mathologer  8 лет назад +3

      +BleuBear Well, since you made it to 16:31 you get my seal of approval anyway :)

  • @Hwd405
    @Hwd405 8 лет назад +7

    Thanks for this video - there aren't many other videos about explaining analytic continuation or what these divergent sums really mean, and you "summed" it all up really succinctly. Another very interesting place that these sums pop up are in real life - calculations in string theory and of the casamir effect seem to suggest that certain values are actually equal to divergent series like 1^3+2^3+3^3+..., and interestingly enough experiments to determine these values seem to agree with the value of the series when defined by the function's analytic continuation at that point. Spooky!

    • @Mathologer
      @Mathologer  8 лет назад +1

      +Hwd405 Actually this is something else I'd really like to do, explain how exactly the Casimir effect can be calculated using 1^3+2^3+3^3+... . The usual "just do it" physics explanations are nice but in the end just don't do it for me :)

  • @shantanupratapsingh7807
    @shantanupratapsingh7807 Год назад +2

    A blatant abuse of concept of infinity.

  • @furrball
    @furrball 8 лет назад +35

    All I know as a programmer, is that if you keep adding up positives and get a negative result, you probably had an overflow. We can fix that by putting more bits into our sum accumulator. Unfortunately, if we're adding up an infinite amount of positives, there aren't enough resources in the universe to make the variable big enough to hold the result, hence it will always overflow. It's all clear now! yay me! ;-)

    • @snbeast9545
      @snbeast9545 6 лет назад +2

      You could just define 1 + 2 + 3 + 4... as -1/12, just like how pi and e are usually defined in programs instead of calculated.

    • @noobita4983
      @noobita4983 6 лет назад +1

      Alessandro Ghignola Grats you broke the code!

    • @dragonsdream4236
      @dragonsdream4236 6 лет назад +3

      But I don't think overflow applies here, ramanujam is just performing simple arithmetic operations on the whole infinite series, not adding it integer by integer as a program would.

    • @anandsuralkar2947
      @anandsuralkar2947 6 лет назад

      I m.studying computer science engineering but all i get to learn at my college is total shit help me..i want to learn cse

    • @Slackow
      @Slackow 6 лет назад

      Alessandro Ghignola it’s not just negative, it’s also a fraction. So you’d never get a fraction from adding integers. Even with overflows. This has nothing to do with overflows.

  • @Virtuoso80
    @Virtuoso80 7 лет назад +58

    Ganesh scared the crap out of me at 4:02

  • @kyleserrecchia7234
    @kyleserrecchia7234 8 лет назад +17

    this is awesome i did not mind the length one bit because it was all relevant and interesting and developed very well

    • @Mathologer
      @Mathologer  8 лет назад +9

      +Kyle Serrecchia That's great, quite a common response which means that I'll probably do more videos like this in the future :)

  • @mahendrapalla7059
    @mahendrapalla7059 3 года назад +1

    If possible can any one solve 1+2+3+4+........ = 4
    The video you seen ,problem is derived by Ramanujan sir, if any one solve this they also become ramanujan

  • @MrBeen992
    @MrBeen992 4 года назад +13

    4:02 DAMN ! I HAD A HEART ATTACK !

  • @mohityadav21
    @mohityadav21 2 года назад +5

    I got scared every time Ganesha appeared with that scary sound.

    • @grewknowledge8750
      @grewknowledge8750 3 месяца назад

      abe mc ahir itna mat dar teri maa pujti hai unhe

  • @1ucasvb
    @1ucasvb 8 лет назад +9

    Can you go more deeply into analytical continuation of the Riemann Zeta? It's where the magic happens, but you skipped it!

    • @Mathologer
      @Mathologer  8 лет назад +14

      +1ucasvb Not just the Riemann Zeta function. What I would really like to do is a video on visualising analytic functions. Absolutely beautiful stuff, but definitely worth a separate video :)

    • @1ucasvb
      @1ucasvb 8 лет назад +2

      +Mathologer I'm actually planning a bunch of visualizations for analytical functions myself. It's a really great topic that needs more love from a general audience!
      Looking forward to your videos on it! :)

  • @1nd93dk3
    @1nd93dk3 4 года назад +8

    I reached the -1/12th level of enlightenment

  • @swissyodeler6970
    @swissyodeler6970 6 лет назад +52

    4:01 Watch this in a dark room late at night.

    • @shivansh5579
      @shivansh5579 5 лет назад +2

      with that sound its effect is increasing😂😂

    • @joseXPOP101
      @joseXPOP101 4 года назад

      Doing that rn Chief

  • @CHAMP_GUY
    @CHAMP_GUY 3 года назад +3

    S. Ramanujan did this without any college degree without any internet under extreme poverty under Britisher.

    • @sssrrr1988
      @sssrrr1988 3 года назад

      Well these things were coming to him, what comes to me is mosquitos
      😭😭😭

  • @AERight462
    @AERight462 6 лет назад +6

    even now i dont understand this .....ramanujan, why did you do this to us?😂😂😂😂😂😂

  • @HDitzzDH
    @HDitzzDH 4 года назад +8

    7:28 Correct me if I'm wrong, but when it comes to the geometric series the absolute valur of r must be strictly

    • @u.v.s.5583
      @u.v.s.5583 4 года назад +5

      But now imagine you are doing a hard physics problem and get this sum as the answer, and you know the sum exists. Do you say, no, the sum does not exist, or do you try to generalize the very concept of the sum? Of course, you generalize the concept of the sum, and this is what one does here. College calculus is out at this point.

  • @whatby101
    @whatby101 8 лет назад +24

    As a student only in pre-calc, i genuinely look forward to working with numbers such as these someday.
    On a side note i watched the whole video and everything made perfect sense, thanks for making it so clear.

    • @kaihulud87
      @kaihulud87 8 лет назад +3

      +whatby101 Mathematics is a very interesting field and its amazing that people can be so intrigued by it no matter their education!
      I struggled to love maths for awhile now but I like to think I see the inherent beauty in it now.
      Before he announced it but showed us the complex realm, I was freaking out because it dawned on me that he was about to mention the Riemann-Zeta function which in itself I tried to understand awhile back and walked away agreeing to disagree with the maths..hah

    • @whatby101
      @whatby101 8 лет назад

      +Password1andUsername That's not really an option for me. Even if I myself am capable of just skipping calculus, I am only in high school. Ap Calc is the highest level class they offer. I will take that junior year, then the following year I plan to take 3 different science classes and take a class on statistics.
      Sadly in any public school, there are not enough mathematically gifted students for there to be an even higher level course. At best I can take a summer class at a college either this or next year.

    • @whynot1150
      @whynot1150 8 лет назад

      This happened to me as well I took AP calc this past year as a junior, and I am not without a math class. To fix this problem I made a deal with a college nearby, and now I am able to take further math classes there. I don't know if that is a possibility for you, but it was the only way for me, for my school only offers two AP classes that I haven't yet taken. Hope you are able to take more maths instead of having a gap year.

    • @lamnguyen-uh4tz
      @lamnguyen-uh4tz 8 лет назад +1

      I have an option for you. Hang out with us on math.stackexchange.com We have tons of smart people, and we're always willing to explain super weird topics (plus we can help with calc if you need.)

  • @BillyBuerger
    @BillyBuerger 8 лет назад +35

    The part that bugs me about this and other things I've seen about infinite series is that people just re-order the sequence and say things like "oh, we'll just put these here." as if that is fine and doesn't have any affect on the output. So you do something that doesn't make sense and then use that to prove something that doesn't make sense. Sure. For instance, if...
    C = 1, 2, 3, 4, 5...
    Then 4C would be ...
    4C = 4, 8,12, 16, 20...
    But instead, you decide you will change 4C to be...
    4C = 0, 4, 0, 8, 0, 12, 0, 16, 0, 20...
    By lining up the number however you please, you are ignoring the sequence and changing it. So of course when you then subtract your adjusted sequence from your initial sequence you don't get what would make sense which is...
    -3C = -3,-6,-9,-12,-15...
    Maybe there is a reason to change the sequence. But if so, no proof was supplied for doing so. Is there a proof for infinite series that explains why you can change the sequence?

    • @Mathologer
      @Mathologer  8 лет назад +14

      If you listen carefully it should become clear that the "just do it" approach that you are worried about never counts as a proof to start with and is only used as a quick tool to build some intuition for what to aim for. When it is and when it is not okay to reorder and rearrange series is something that is sorted out whenever one introduces one of these different ways to sum series :)

    • @BillyBuerger
      @BillyBuerger 8 лет назад +3

      Thanks for the response. I appreciate you taking the time to answer. Although it leaves me wondering what the point of this is?

    • @Mathologer
      @Mathologer  8 лет назад +11

      Well, one of the points is to find this analytic continuation of the Riemann zeta function which is a very big deal in math :)

    • @BillyBuerger
      @BillyBuerger 8 лет назад +3

      Okay, I did some more reading and some articles that are critical of the Numberphile video on this same topic. Seems the confusion being the = part. As you state near the end, the answer on a test of 1+2+3+4... would not be -1/12. But you can use the methods you discuss to derive a value from divergent series that otherwise doesn't have a values.

    • @Mathologer
      @Mathologer  8 лет назад +11

      Infinity has many VERY PRECISE meanings within mathematics depending on the context it is used in. One thing it definitely does not mean is "undefined", at least not in mathematics. Also, clearly, none of this can possibly originate in the work of string theorist since there was no string theory in Ramanujan's time. In fact, most of what I talk about in this video dates back more than a hundred years (Cesaro sums, Zeta function). If you are interested in historical details maybe just google some of the terms that pop up in this video :)