Integrating the boi of your Putnam dreams ( Sophomore's dream: Integral x^-x from 0 to 1 )

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  • Опубликовано: 16 дек 2024

Комментарии • 727

  • @gaetanramos7903
    @gaetanramos7903 6 лет назад +1749

    > assuming you can interchange integral and sum signs without proving it first
    REEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

    • @PhilGarmann
      @PhilGarmann 6 лет назад +219

      Flammable Maths By Tonelli’s theorem you can interchange the integral and the sum since your integrant is ≥0 on the interval you’re calculating the integral over ie. [0,1]

    • @RadicalSolver
      @RadicalSolver 6 лет назад +81

      Philip Garmann
      LOL
      The main property required is that the integrand is integrable on every compact subinterval of the open half-line (0,\infty).

    • @GaetanAlmela
      @GaetanAlmela 6 лет назад +29

      Hey we have the same first name :D

    • @davidkippy101
      @davidkippy101 6 лет назад +42

      It's very intuitive because integrating a sum lets you split it into several integrals of each component of the sum. Then you can just sum up the integrals.

    • @ninakoch1799
      @ninakoch1799 6 лет назад +17

      It‘s trivial😂

  • @TheGamer583
    @TheGamer583 6 лет назад +1334

    This is actually pretty amazing, because 1/(j^j) is essentially j^(-j), which is practically what we started with, x^(-x). So theoretically we converted a continuous sum (the integral) into a discrete sum of literally the same form! But instead of 0 to 1, we have 1 to infinity.

    • @PavelSTL
      @PavelSTL 6 лет назад +208

      I wonder if this fact can be used to show that the set of real numbers is bigger than the set of natural numbers (instead of Cantor's diagonalization proof)

    • @RadicalSolver
      @RadicalSolver 6 лет назад +31

      TheGamer583
      Why don't you try doing a Riemann Sum computation of this integral?

    • @kichveellc275
      @kichveellc275 5 лет назад +23

      =1.29129

    • @josephgrossenbacher7642
      @josephgrossenbacher7642 5 лет назад +4

      @@PavelSTL , a look at "the Hilbert hotel" ( &/v at "the hyperwebster" ) will give you a negative answer ... !!!

    • @intfxdx
      @intfxdx 5 лет назад +14

      Wonder what other functions have \int_0^1 f(x) dx becoming \sum_{j=1}^\infty f(j) :) Great video Flammable Maths!

  • @tissuepaper9962
    @tissuepaper9962 6 лет назад +354

    "Infinity boi" is now my new favorite phrase

  • @g0rgth3b0rg
    @g0rgth3b0rg 6 лет назад +251

    I love when the Gamma Function pops up in these crazy integrals.

  • @oliverhees4076
    @oliverhees4076 6 лет назад +744

    Drinking game: take a shot anytime he says "boi" or "boiz"

    • @mcmage5250
      @mcmage5250 6 лет назад +7

      Oliver Hees j dond ghe vhallenve alr2adg it went fins i fhink

    • @redaabakhti768
      @redaabakhti768 6 лет назад +10

      you ll solve riemann conjecture but only drunk people will understand you ll forget the solution when sober

    • @redaabakhti768
      @redaabakhti768 6 лет назад

      this is your destiny

    • @alsoeris
      @alsoeris 5 лет назад +3

      Crack open a cold one with the boiz

  • @jony7779
    @jony7779 6 лет назад +594

    Who would win? The proof of Fermat's Last Theorem or
    O N E I N F I N I T I B O I

  • @46pi26
    @46pi26 6 лет назад +999

    Infinity bois are the best bois

  • @benjamincalloway
    @benjamincalloway 4 года назад +431

    Sorry sir, I couldn't hear you over the sound of my engineering approximations

    • @gregoriousmaths266
      @gregoriousmaths266 4 года назад +1

      Mr. Skeltal hahahaha

    • @Dawatehaq786
      @Dawatehaq786 4 года назад +1

      Trigonometry for AS and A level ruclips.net/video/-WzZRx4vVxI/видео.html
      Watch and share and subscribe our channel

  • @drpeyam
    @drpeyam 6 лет назад +386

    For people saying that this video is on my channel: I promise you that we came up with this idea independently a couple of weeks ago, it’s just a pure coincidence that our videos got uploaded almost on the same day!

    • @jeromesnail
      @jeromesnail 6 лет назад +8

      Dr. Peyam's Show haha I was thinking "I already saw this one". You should have made it in German ;p

    • @michaelempeigne3519
      @michaelempeigne3519 6 лет назад +2

      Can you do a video on nonlinear PDEs ?

    • @porter_moody
      @porter_moody 6 лет назад

      i dont believe it

    • @djameleddinekebiche1268
      @djameleddinekebiche1268 6 лет назад +64

      Oh boy here we go again, it's the Leibniz-Newton controversy again.

    • @MrAzizomer
      @MrAzizomer 6 лет назад +2

      calculate for me the probability of that happening

  • @bartoszwojtowicz8770
    @bartoszwojtowicz8770 6 лет назад +111

    Now that's the 'recommended for you' I was hoping for

  • @nenume00
    @nenume00 6 лет назад +560

    wait wtf memes and maths?

    • @notsojharedtroll23
      @notsojharedtroll23 6 лет назад +49

      This boi is the only English speaker boy that uses the pacman :V
      Kudos from Mexico xd

    • @general_prodigy
      @general_prodigy 4 года назад +1

      It's like oil and water, or rather a poly protic compound and a non-polar compound
      Chemistry bois will know this

  • @SimonClark
    @SimonClark 6 лет назад +560

    This was fun! You're a natural teacher - I look forward to seeing what you will upload in the future!

    • @potatopassingby
      @potatopassingby 6 лет назад +4

      hello simooooon :D i have no idea how i found your comment in this video, it was randomly recommended to me lol

    • @MoJohnnys
      @MoJohnnys 6 лет назад +9

      I sense fanfiction probabilities...🙈

    • @soyoltoi
      @soyoltoi 6 лет назад +8

      Top 10 anime crossovers

    • @Neo-br3uc
      @Neo-br3uc 6 лет назад

      Ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh myyyyy

    • @alexandernissen4353
      @alexandernissen4353 6 лет назад +1

      I agree dr. Clark!

  • @chriss6356
    @chriss6356 6 лет назад +286

    commuting an infinite sum and integral without hesitation *im shook*

    • @elfaroukharb3979
      @elfaroukharb3979 6 лет назад +86

      My real analysis professor would've had a heart attack seeing this.

    • @hansenchen1
      @hansenchen1 6 лет назад +19

      and +Elfarouk Harb: This could be proved using the Fubini's theorem.

    • @WhisDragonBallSuper
      @WhisDragonBallSuper 5 лет назад +3

      @@hansenchen1 he should have atleast written it

    • @chihebsaidi2054
      @chihebsaidi2054 4 года назад +1

      @@hansenchen1 Elaborate please

    • @stephankarl1301
      @stephankarl1301 4 года назад +14

      @@chihebsaidi2054 Der Beweis ist dem Studenten als Hausaufgabe aufgegeben

  • @evanbelcher
    @evanbelcher 6 лет назад +34

    This was fun to watch. When he did substitutions so it fit perfectly into the gamma function template and things started canceling out I was blown

  • @janderson2709
    @janderson2709 6 лет назад +126

    This is how good I want to be one day.

    • @FiremarkPl
      @FiremarkPl 11 месяцев назад

      Hello, im from future! Have you achieved the goal?

  • @badjumpcuts6599
    @badjumpcuts6599 6 лет назад +85

    I laughed.
    I cried.
    You, sir, are an artist

  • @1anya7d
    @1anya7d 6 лет назад +115

    the BOI

  • @GeodesicBruh
    @GeodesicBruh 5 лет назад +90

    When I’m faced with a hard Integral I usually just call the integrand f(x) and then I say let F(x) be the integral of f.
    I don’t know why you guys use these “techniques of integration”.

    • @isaacdeutsch2538
      @isaacdeutsch2538 4 года назад +26

      And here we have a physicist

    • @godson200
      @godson200 4 года назад

      It is a standard method of solving...what you said... I.e we take F(x) is the integral and then simplify... We have a whole chapter of 45 pages on it

    • @davideranieri5553
      @davideranieri5553 4 года назад +16

      That actually does happen e.g. the special functions of analysis. Realize you can't find the antiderivative of say 1/ln(x)? Slap the name li(x) on it and call it a day

    • @appa609
      @appa609 4 года назад +9

      Exam: Find the solution to this equation
      Me: Def: x a real number such that it satisfies this equation.
      x is the solution.

    • @k_meleon
      @k_meleon 4 года назад +2

      @@appa609 well that's kinda what the root is in a sense. sqrt(n) is the positive number x such that x^2 = n

  • @quantumchill5237
    @quantumchill5237 6 лет назад +150

    Putnam memes for Sophomore dreams

  • @drpeyam
    @drpeyam 6 лет назад +134

    Beautiful :)

  • @PalikkaFilms
    @PalikkaFilms 6 лет назад +56

    you lost me at infinity boi

  • @zachydrogeo
    @zachydrogeo 6 лет назад +19

    this video is making me relive uncomfortable traumatic experiences from calc 2. so glad I'm in the cozy arms of simple calc 3

  • @mounodeepchakraborty3190
    @mounodeepchakraborty3190 6 лет назад +14

    Papa Flammy, your way of explaining math problems is very unique and it goes straight to the head !! your attitude and way of explaining things is so cool and I never get stressed out.. wish I could get teachers like you in my graduation !! 😊😊😊

  • @nestorv7627
    @nestorv7627 6 лет назад +12

    please keep doing these beautiful integrals

  • @kevinchang1371
    @kevinchang1371 4 года назад +3

    Dankest maths channel I have ever seen 🐸👌🏻🎩

  • @Crustyislooking
    @Crustyislooking 4 года назад +22

    Me after finishing AP Calc: Damn I can finally watch videos on calculus and know what’s happening.
    Nvm

  • @TuningFreak23
    @TuningFreak23 6 лет назад +43

    Its 1:30 AM I'm high and watching this. Dudeeee

  • @jerrekedb
    @jerrekedb 6 лет назад +2

    I love how int(x^-x dx,x=0,x=1) = sum(j^-j,j=1,inf). Beautiful symmetry there

  • @Yatukih_001
    @Yatukih_001 6 лет назад +1

    Why thank you!!!!!The mathematics channels are among my favorite youtube channels. Enormous amount of truth there!!! Amazing work and really well done and wishing everyone the best!!

  • @asificare7985
    @asificare7985 3 года назад +1

    I have no words to describe how beautiful the final result is. Also, this was one of your very well made videos :)

  • @Storm-wk8hy
    @Storm-wk8hy 4 года назад

    I clearly have no words to appreciate you......i was like the type of person who hates integration the most....but the way u approached each and every questions bloomed up an interest in me to see more of ur videos....u really changed me a lot...i dont know whether you will see this comment or not...but im proud to say u r my frst subscriber related to MATHS...thumbs up bro..and GG
    LOVE FROM INDIA

  • @cliffordwilliams9597
    @cliffordwilliams9597 4 года назад

    I barely understood what was going on and I LOVED IT! How did I just discover this channel? I love that the answer at the end was "like, 1.29something...?" Who cares about the answer when you have this beautiful process!

  • @nitinsadras
    @nitinsadras 6 лет назад +28

    i n f i n i t y b o i

  • @APPLEZACKS
    @APPLEZACKS 6 лет назад +7

    Literally liked the video before I even started watching it

  • @postnubilaphoebus96
    @postnubilaphoebus96 5 лет назад +6

    I don't understand a lot about maths but it seems like substitution is a very important technique for proofs. Also, it's handy to know similar functions so you can look at similarities.

  • @skippycochrane1839
    @skippycochrane1839 6 лет назад +2

    i love the way you teach x) if my lecturer spoke like this i would be laughing none stop

  • @tay1545
    @tay1545 6 лет назад +4

    I just started learning calculus a few months ago, these videos are awesome because you do all the basic steps as well like at 1:13 , at my university the professors and teachers and even the university textbook never showed that step, it just showed 1:36 lol, great vids dude you make learning math seem just fine to a laymen.

  • @DiamondSane
    @DiamondSane 6 лет назад +4

    The more I see those integration puzzles the more I love numerical methods.

  • @paulg444
    @paulg444 5 лет назад +1

    I like the way he pulled the -1^k /k! in from the cold !!

  • @Ryan-gq2ji
    @Ryan-gq2ji 4 года назад +2

    I started panicking when you wrote dx = -e^u du, but I calmed down when you subtly rewrote it as -e^-u du
    xd

  • @louismolywacky634
    @louismolywacky634 5 лет назад

    So beautiful solution with your rythmical good tempo as well as german like intonation and pronunciation. I love it.

  • @przemysawrusin599
    @przemysawrusin599 6 лет назад

    You make me smile a little bit every time you say 'infinity boi' :) subscribed!

  • @_DD_15
    @_DD_15 6 лет назад

    We have the same way of reasoning and learning as far as I have seen. You don't make many analogies, I love your videos, keep going mate.

  • @regulus2033
    @regulus2033 5 лет назад +2

    Really interesting integral, thank you! The nice thing is that we integrate x^(-x) and get sum of k^(-k), very symmetric thing :)

  • @alexandrokivistov8983
    @alexandrokivistov8983 5 лет назад

    Now this is my favorite video of your channel

  • @LaTortuePGM
    @LaTortuePGM 6 лет назад +4

    lol reminds me that time when i asked on >implying what was the sum from n=1 to infinity of 1/x^x and someone said it probably didn't have a closed form but that it was equal to this integral.

  • @ChrisLuigiTails
    @ChrisLuigiTails 6 лет назад +1

    Infinity boi
    Memes and maths. Subscribed.

  • @seanlewis3867
    @seanlewis3867 3 года назад

    It is very interesting the way your final result looks almost the exact same as your original problem, just in a discrete form

  • @robertl.crawford4369
    @robertl.crawford4369 3 года назад +1

    Nice job man, I really liked it and you!

  • @ianprado1488
    @ianprado1488 6 лет назад +4

    There is some interesting semmetry between the initial problem and the solution

  • @yeast4529
    @yeast4529 6 лет назад +3

    Maths and memes. My new home

  • @almanahulzilnicdesuceava5379
    @almanahulzilnicdesuceava5379 6 лет назад +29

    I showed this work to my lil sister and just laughted and said "what.s his favourite pokemon?" :))))

  • @charlie3k
    @charlie3k 6 лет назад +49

    ah so you're an English major

    • @charlie3k
      @charlie3k Год назад

      I’m just now coming back to this video 4 years later and now I fully understand it after taking calculus courses! I don’t even remember commenting on this video either.

  • @kamrons8250
    @kamrons8250 6 лет назад +3

    Damn I miss calc. Saw this video on recommendation, very easy to follow and nicely explained.

  • @CossZt6
    @CossZt6 6 лет назад

    That (-1) getting canceled out was one of the most satisfying things I've seen in some time lately

  • @kevinmartin7760
    @kevinmartin7760 6 лет назад +2

    I find it interesting that the integral from 0 to 1 of x^-x dx ends up being the sum from 1 to infinity of j^-j

  • @illumiyokai
    @illumiyokai 6 лет назад +11

    I saw boi and I clicked.

  • @arthurgames9610
    @arthurgames9610 5 лет назад +1

    Waaaaai. X^-x=1/x^x. We can call it f(x). So, integral of f(x) at 0 to 1= 1/1^1 +1/2^2... but, this is exaticly f(1) + f(2)...
    Edit: im sorry if us duficult to understand this, its because im Braziliam, im not so good at English

  • @simonsidorov8315
    @simonsidorov8315 6 лет назад +1

    It's an interesting result that the integral of x^{-x} is equal to the sum of the very same thing with x taking discrete positive values. At least it's the first time I see a function with a property like that

  • @adamtaylor1739
    @adamtaylor1739 6 лет назад

    How have I only just found this channel? It's awesome!

    • @adamtaylor1739
      @adamtaylor1739 6 лет назад

      Hey, can I ask what your 'day job' is?

  • @wildatakalamingan2635
    @wildatakalamingan2635 6 лет назад +1

    First video to reach 100k+ views. proud of you :)

    • @Hawilabas
      @Hawilabas 4 года назад

      It's me, I used my mom phone to watch and commented, now you already passed 100k subscribers, very proud of you papa flammy, time flies~

  • @aniruddhvasishta8334
    @aniruddhvasishta8334 4 года назад +1

    It's pretty neat that the integral from 0 to 1 of x^(-x) is just equal to the sum from 0 to infinity of x^(-x).

  • @pandas896
    @pandas896 5 лет назад +1

    I am happy , I was able to do this question in another way.

  • @blazep5881
    @blazep5881 6 лет назад +33

    Me me interesting boi

  • @darthyoda4085
    @darthyoda4085 5 лет назад +3

    I think it's surprising that the integral from 0 to 1 of x^(-x) is exactly the sum from 1 to infinity of x^(-x)

  • @kimmovillacorta7677
    @kimmovillacorta7677 5 лет назад

    Very nice solution. A seemingly impossible problem... Led to an elegant solution

  • @erwinrojasarabia
    @erwinrojasarabia 6 лет назад

    I saw your videos thinking I was subscribed lol, definitely your charisma makes me concentrate completely on the video haha

  • @hoodedR
    @hoodedR 4 года назад +1

    Why am i watching this again...I just saw it two days ago, and now this is the third time. Oh well. Hi Papa!

    • @PapaFlammy69
      @PapaFlammy69  4 года назад

      Glad to see you back then Ranjan! xD

  • @unsnowki
    @unsnowki 4 месяца назад

    I understand at most half of it but this is BEAUTIFUL

  • @testusernameyoutube1
    @testusernameyoutube1 4 года назад +5

    Find someone who looks at you like our boi looks at the integral at 6:06

  • @jimnewton4534
    @jimnewton4534 5 лет назад

    nice development. Not very difficult, but you have to make the right magical substitutions. Congratulations.

  • @lukehatcher98
    @lukehatcher98 4 года назад +1

    Beautiful result.

  • @meccamiles7816
    @meccamiles7816 4 года назад +1

    That was god-damn beautiful.

  • @sorcererstone3303
    @sorcererstone3303 6 лет назад

    Another great example. I need to watch how to solve an integral from here everyday. That will make my day!

  • @SteamPunkLV
    @SteamPunkLV 6 лет назад

    my favorite part was when you factored out the (-1)^k to make a (-1)^2k xD
    awesome video!

  • @khair7549
    @khair7549 4 года назад

    We need more passionate people like u in the world

  • @michael-gary-scott
    @michael-gary-scott 6 лет назад

    Honestly the title is why I'm here. Subbed.

  • @christophercampbell6906
    @christophercampbell6906 5 лет назад +1

    prob bois saw the reciprocal of the scaling factor for a gamma density right away

  • @beenchillinmyself
    @beenchillinmyself 6 лет назад

    BEST MATH PERSONALITY ON RUclips BOII

  • @brandonwhitaker8468
    @brandonwhitaker8468 6 лет назад +4

    6:42 I was very tense up until that moment

  • @jeevanroy3409
    @jeevanroy3409 5 лет назад

    Awesome dude....... Do more videos just like this....... All the best.... 👍💯

    • @jeevanroy3409
      @jeevanroy3409 5 лет назад

      @@PapaFlammy69 may I get your mail ID😅

  • @ooffoo5130
    @ooffoo5130 4 года назад +1

    I have no clue how to do calculus and I usually understand about 10% of what's going on but I love this guy's videos

  • @garydunken7934
    @garydunken7934 6 лет назад +7

    Good boi

  • @sab1862
    @sab1862 5 лет назад +2

    Wow, integrate [x=0~1] x^(-x) dx is EXACTLY same with sum [x=1~Inf] x^(-x)? How nice it is! :D

  • @babaganamuktar9518
    @babaganamuktar9518 3 года назад

    I think the answer might be -2.
    Try integrating it without introducing the sum notation. It's pretty amazing.
    Thanks for uploading this video, looking forward for more.

  • @maerski5171
    @maerski5171 5 лет назад

    i am still too young for this, but videos like this really fascinated me despite not understanding stuff

  • @debajyotisg
    @debajyotisg 6 лет назад

    These videos make me so happy!

  • @mokouf3
    @mokouf3 5 лет назад +2

    You can do one more step!
    It is equivalent to Sum(x=1 to ∞, x^(-x))
    The integrand of original integral is exactly same as the addend of the infinite summation!

    • @frenchimp
      @frenchimp 2 года назад

      Yes, that's a mesmerizing result!

  • @ninakoch1799
    @ninakoch1799 6 лет назад

    Boi, that helped me a lot, thanks daddy❤️ i only just found your channel, now i‘m binge watching😂😍

  • @KL005
    @KL005 6 лет назад +1

    Forget flammable, you're on fire! What a hottie!

    • @KL005
      @KL005 6 лет назад

      Marry me please

    • @KL005
      @KL005 6 лет назад

      Noooooo....then again I'm not surprised. Whoever has you is lucky! 😘

  • @stayawayfrommrrogers
    @stayawayfrommrrogers 6 лет назад +5

    “This infinite boi”

  • @taherhabib3180
    @taherhabib3180 5 лет назад

    Boi! Too much awesomeness packed in one human!

  • @joshuabonet
    @joshuabonet 3 года назад

    This is such a badass Integral Boi

  • @andresxj1
    @andresxj1 6 лет назад +2

    This is indeed a flammable day!

    • @blackpenredpen
      @blackpenredpen 6 лет назад +1

      Andy Arteaga heyyyy Andy!!!

    • @andresxj1
      @andresxj1 6 лет назад

      blackpenredpen Hii! Congratulations for your first live video!

    • @blackpenredpen
      @blackpenredpen 6 лет назад

      Andy Arteaga thank you!!!

  • @ANDRY4693
    @ANDRY4693 5 лет назад

    you're BIG man, good job!

  • @strengthman600
    @strengthman600 6 лет назад +1

    Jens you're the best

  • @gltchey
    @gltchey 6 лет назад +8

    integral from 0 to 1 of 1/x^x dx = sum from 1 to infinity 1/k^k
    cool

    • @sergiokorochinsky49
      @sergiokorochinsky49 6 лет назад +1

      ...I just can't see an intuitive geometric argument to explain why "0 to 1" became "1 to infinity".

    • @erenlapucet398
      @erenlapucet398 6 лет назад

      I wonder now if it's possible to find a function whose integral is finite and is exactly equal to its infinite sum with the same boundaries (obviously one of the boundaries being infinity)

  • @akarshkumar0101
    @akarshkumar0101 6 лет назад

    You are such a good teacher and are so relatable 😂👌 keep making videos

  • @joelsagflaatholmberg3922
    @joelsagflaatholmberg3922 6 лет назад +1

    I wish that you could be my teacher when I'm done with elementary school. You are awesome!

    • @pendulousphallus
      @pendulousphallus 5 лет назад

      Is North American education so bad that the rest of the world has their kiddos watching and following along with these videos as early as elementary school?