ONE NEAT PROOF! Deriving the EULER DEFINITION of the Gamma Function!

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  • เผยแพร่เมื่อ 18 ธ.ค. 2024

ความคิดเห็น • 120

  • @stimpyfeelinit
    @stimpyfeelinit 5 ปีที่แล้ว +91

    I HOPE YOU AGREE WITH ME
    *vague germanic threat*

  • @ryanmuller9497
    @ryanmuller9497 5 ปีที่แล้ว +115

    That moment when Papa Flammy defines n as being strictly less than z and then takes the limit as n approaches infinity while keeping z finite... (I assume that there's a second case to the derivation in which n is greater than z that ends up with the same result at some point down the track, but still a bit slack :P )

    • @מיכאלקונטרוביץ
      @מיכאלקונטרוביץ 5 ปีที่แล้ว +20

      but generally z is a complex number,so z>n is meaningless,untill we are speaking of the modulus

    • @sergiokorochinsky49
      @sergiokorochinsky49 5 ปีที่แล้ว +31

      This reminded me a class in Materials Science when the teacher approximated sin(theta) by theta for very small angles, and then proceeded to integrate between 0 and 2pi. :-)

    • @epicmorphism2240
      @epicmorphism2240 4 ปีที่แล้ว +1

      @arabicboi Yes you‘re right but than it also wouldn’t make sense to define n < z. Please correct me if I‘m wrong but I think this proof is not valid.

    • @rish5827
      @rish5827 4 ปีที่แล้ว +1

      @@epicmorphism2240 I don't think it's meant to be an entirely rigorous proof, just sort of showing the general ideas

    • @epicmorphism2240
      @epicmorphism2240 4 ปีที่แล้ว +1

      Rish There is a difference between rigorous and wrong…

  • @Silver_G
    @Silver_G 5 ปีที่แล้ว +68

    10:01
    About that n = [ 2/1 • 3/2 • 4/3 •…• n/(n-1) • (n+1)/n], shouldn't it be left with n + 1 after those cancellation?

    • @OunegNebty
      @OunegNebty 5 ปีที่แล้ว +11

      Yes I Had the same question papa

    • @thomaskim5394
      @thomaskim5394 5 ปีที่แล้ว +4

      That needs to be more clear. Just saying that it does not matter in limit would not be enough.

    • @Downloader77
      @Downloader77 5 ปีที่แล้ว +2

      Well spotted @Silver-G

    • @reetanshukumar1865
      @reetanshukumar1865 5 ปีที่แล้ว +5

      it should be n/n-1 in the end

    • @a.e.6994
      @a.e.6994 4 ปีที่แล้ว +4

      It's a very good question. But see in the video by min 10:24. He changed (n+1)/n into 1+(1/n). In this version let n run to infinity. So you have n=n.
      The idea of reetanshu is also remarkable. But you have to consider that this is the penultimane term in the equation.

  • @bluebears6627
    @bluebears6627 5 ปีที่แล้ว +38

    "If you have one apple then you still have one apple" -one random flammy boi

  • @mrandersonpw53
    @mrandersonpw53 5 ปีที่แล้ว +25

    When he started to taking the limit of n, you can asume z fixed (but z except -infinity or infinity) . For zn is a little bit more complicated, but I think it works too using horizontal truncation of lebesgue measure.
    If z=n, I don't know.
    He's fine :)

  • @yanghwanlim4499
    @yanghwanlim4499 5 ปีที่แล้ว +5

    When deriving the partial integral of the { t^(z-1)(1-t)^n }, it is much simpler to do it in case of n=3 as an example.
    Then the resulting form clearly hints us about the form in case of n.
    For the purpose of explaining , I think this way is better. Don't you think?

  • @enginakkent5042
    @enginakkent5042 5 ปีที่แล้ว +16

    Besides the random groaning at 00:03 I have something to tell you and I hope you see this.
    I am an engineering student whose relation with mathematics kind of became sour after entering university ( there are several reasons but I don't want to get into them). Although, I have no idea about how I discovered your videos, I'm very glad that I did. There are something in your videos that made me realise how interesting and enjoying math really is and I should not give up so easily due to my failures or succeses of others. I would like to write more but i don't want it to get more boring. I just want you to know that I owe you a lot. Thank you so much and please keep up with your videos :)

  • @9y028
    @9y028 5 ปีที่แล้ว +9

    1:55 You said n is strictly less than z. If you let n go to infinity, does that mean that this only works for z also going to infinity?

  • @zactron1997
    @zactron1997 5 ปีที่แล้ว +8

    8:24 How about the Ganna function?

  • @TheLevano22
    @TheLevano22 4 ปีที่แล้ว +4

    9:56 the way you explained it I got the idea that the final product in the brackets would leave us with just the "n+1" term, without it being divided by anything. Every previous term's numerator and following term's denominator will continue to cancel out, including denominator of (n+1)/n term. Leaving us with just "n+1". Someone pls prove me otherwise cause I can't properly continue watching the video without resolving this misunderstanding.

    • @AlexHernandez-yj6qe
      @AlexHernandez-yj6qe 10 หลายเดือนก่อน

      Lmao, I'm crossing with the same question. I've started studying the gamma function and saw a similar process but the product is set equal to (n+1) not n. I've tried to make sense out of it, but since I couldn't, I stuck with the other method.

  • @gaetanodagostino7127
    @gaetanodagostino7127 5 ปีที่แล้ว +2

    I once read this on a book called "Funzioni Speciali" From L. Gatteschi. Never found that book again.

  • @TheNachoesuncapo
    @TheNachoesuncapo 5 ปีที่แล้ว +3

    that was a seriously good video!thanks for the outstanding great work as always

  • @neilgerace355
    @neilgerace355 5 ปีที่แล้ว +7

    9:57 cancelling everything out, you end up with n+1 ...? What did I miss?

    • @SvenBeh
      @SvenBeh 5 ปีที่แล้ว +2

      You're right.

  • @kalvin90210
    @kalvin90210 5 ปีที่แล้ว +10

    Where is the uncut version on your second channel my twink boi???🍄

  • @kevind.shabahang
    @kevind.shabahang 3 ปีที่แล้ว +2

    Lmao literally the funniest math tutorials! Bravo! Laughed out loud at 7:26 "we are just going to take the limit of this crap"

  • @MrRyanroberson1
    @MrRyanroberson1 5 ปีที่แล้ว +1

    7:30 another important theorem to mention is that you have finitely many 1 limits, otherwise you're doing an advanced e.

  • @SidneiMV
    @SidneiMV 5 หลายเดือนก่อน

    simply awesome definition for the Gamma function!

  • @papsanlysenko5232
    @papsanlysenko5232 5 ปีที่แล้ว +15

    But shouldn't z also approach infinity, as n approaches infty?

    • @avinashverma2773
      @avinashverma2773 5 ปีที่แล้ว

      Yeah, I have the same question

    • @Dionisi0
      @Dionisi0 5 ปีที่แล้ว

      That's why í disliked this video

    • @RieMUisthegoaT
      @RieMUisthegoaT 5 ปีที่แล้ว +2

      @@Dionisi0 low brain

    • @angelmendez-rivera351
      @angelmendez-rivera351 5 ปีที่แล้ว +3

      He said n < z for the sake of simplicity, since it would make breaking the product the way he did easier, but actually, there is no need for n to be strictly smaller.

  • @FlyingOctopus0
    @FlyingOctopus0 5 ปีที่แล้ว +1

    Actually the integral t^(z-1)(1-t)^n is a beta function with parameters z and n+1. beta function can be rewritten in terms of gamma functions as a fraction gamma(z)gamma(n+1)/gamma(z+n+1). I think this relation was used on the channel, but I don't remember in what video.

  • @Therealpec96
    @Therealpec96 4 ปีที่แล้ว +4

    Thank you folk your video was very usefull, I hope people agree with me

  • @MK-13337
    @MK-13337 5 ปีที่แล้ว +3

    8:50 "I wanna play more with this junk over here"
    I bet you do, huh?

  • @The_Professor_S_
    @The_Professor_S_ 5 ปีที่แล้ว +8

    Was that a 3Blue1Brown-roid?

  • @tianvlasic
    @tianvlasic 5 ปีที่แล้ว

    That yoke at beginning is very funny😂.

  • @a.e.6994
    @a.e.6994 4 ปีที่แล้ว

    Ganz prima Video!! Danke!!

  • @xHyperElectric
    @xHyperElectric 4 ปีที่แล้ว +1

    Where’s the link for the integration by parts uncut version?

  • @bijoydas6044
    @bijoydas6044 3 ปีที่แล้ว

    I have a doubt at 9:47 n=(2/1)*(3/2)*(4/3)*..........*(n/n-1)

  • @davidarenas1156
    @davidarenas1156 5 ปีที่แล้ว +1

    I have a doubt, when you take the limit as n goes to infinit, shouldn’t you just take it on the last term? Because Its like a progression. Sorry for my bad english.

  • @BigDBrian
    @BigDBrian 3 ปีที่แล้ว

    but in the initial series n

  • @The_Professor_S_
    @The_Professor_S_ 5 ปีที่แล้ว

    Papa’s videos are the best way to start the long ass day at work!
    And the Gamma function as derived by DADDY EULER? Even better!

  • @paulestrada961
    @paulestrada961 4 ปีที่แล้ว +4

    When you go from (n/(n-1)) to (n+1)/n is where I stopped the video. There should be more background as to how you can justify using the fact that n=n can be turned into n=n+1 which of course is not an equality.
    Saw one of your snack videos and love all of your content. Was curious how someone else did the i! I remembered that you did a video on it because the video I saw from someone else resorted to approximation rather than a closed form and came here by your link on that video.

    • @PapaFlammy69
      @PapaFlammy69  4 ปีที่แล้ว +4

      I made a complementary video on that actually!

  • @tszhanglau5747
    @tszhanglau5747 5 ปีที่แล้ว +1

    The integral at 17:12 is oddly similar to beta function...I think you could have used it's relationship with gamma function to express the integral in terms of factorials...

  • @agitatethecrystals
    @agitatethecrystals 5 ปีที่แล้ว

    what did you say from 12:27 to 12:29?

  • @RieMUisthegoaT
    @RieMUisthegoaT 5 ปีที่แล้ว +1

    imo the nth integration by parts was more interesting than the Euler definition of the gamma function lol

  • @rot6015
    @rot6015 5 ปีที่แล้ว +1

    Just a comment to increase papa's popularity

  • @mohibmohib6442
    @mohibmohib6442 3 ปีที่แล้ว

    I suggest you a question please answer
    gamma (n + 1/2) as a product what is equal to? how to write with the product symbol

  • @MrRyanroberson1
    @MrRyanroberson1 5 ปีที่แล้ว +2

    nononono 10:05 idk if you realize but you just did n=n+1, which is technically fine for infinitives but is very dubious

    • @angelmendez-rivera351
      @angelmendez-rivera351 5 ปีที่แล้ว

      Ryan Roberson How is it dubious? You literally just said it's fine for infinities. Pick one.

  • @Ricocossa1
    @Ricocossa1 5 ปีที่แล้ว

    "In the real numbers, shit is Abelian." - Flammable Math 2019

  • @ajinaajai550
    @ajinaajai550 4 ปีที่แล้ว

    How can you write a complex number factorial as a real number factorial times's (n+1) .... z ??????

  • @morbidmanatee5550
    @morbidmanatee5550 5 ปีที่แล้ว +1

    Shouldn't the product go from k=1 to n-1 (not n)?

  • @assafabram9649
    @assafabram9649 5 ปีที่แล้ว

    Actually it will be wrong to demand that n will be strictly less then z, because you want to take a limit of n to infinity and don't change z.

  • @soldenstoll8495
    @soldenstoll8495 5 ปีที่แล้ว +1

    Just for fun can you do a video on the integral of sec(x)tan^2(x). It is beautiful because you have to evaluate sec^3(x) which involves coming back to the original integral. Or you could make it a bit harder by doing sqrt(x^2+1).

  • @arnavchaturvedi4818
    @arnavchaturvedi4818 5 ปีที่แล้ว

    For π expansion from '1' to 'n' while expressing 'n' as a finite product you can only pull this upto n-1 as the upper limit then why and how did you go for n as the upper limit. Plz explain.

    • @arnavchaturvedi4818
      @arnavchaturvedi4818 5 ปีที่แล้ว

      @@PapaFlammy69 but still, there limit is applied on that basis it's fine to comprehend but here it's just doesn't go through. Help me with this if you can.

  • @asmasaimun3817
    @asmasaimun3817 10 หลายเดือนก่อน

    here n

  • @martinmaturanaacevedo4618
    @martinmaturanaacevedo4618 6 หลายเดือนก่อน

    im sorry but, why you can cancel out the z/n as n goes to infinity?, i mean, if n goes to infinity, doesnt that mean that z also goes to infinity?

  • @ronpearson1912
    @ronpearson1912 2 ปีที่แล้ว

    Why is the Gamma function used for the ao term of the bessel function of the first kind?

  • @bogdancorobean9270
    @bogdancorobean9270 5 ปีที่แล้ว

    The Gamma function is cool and everything, but are you ever going to do a video on the Borwein integral? :)

  • @Fightclub1995
    @Fightclub1995 5 ปีที่แล้ว +1

    You need some Hagoromo chalk

  • @syedmdabid7191
    @syedmdabid7191 2 ปีที่แล้ว

    Find out the numerical value of Γ(1/3), Γ(1/5) ? Or Γ(1/3) =?, Γ(1/5) =?

  • @ayernee
    @ayernee 5 ปีที่แล้ว

    how the fuck can you take \(n
    ightarrow\infty\) if n in an integer less than z??

  • @campbellmorrison8540
    @campbellmorrison8540 3 หลายเดือนก่อน

    I guess its all about how you look at it

  • @goatmatata2798
    @goatmatata2798 5 ปีที่แล้ว

    Please create a video where u prove gauss's multiplication theorem pleaaaaas

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    Shot clock cheese

  • @bobus_mogus
    @bobus_mogus 5 ปีที่แล้ว

    Will you proof "classical" form of gamma function i.e it's integral representation

    • @bobus_mogus
      @bobus_mogus 5 ปีที่แล้ว

      @@PapaFlammy69 thanks :D

  • @UnordEntertainment
    @UnordEntertainment 5 ปีที่แล้ว

    the limit of ab is not necessarily equal to the limit of a times the limit of b?

    • @UnordEntertainment
      @UnordEntertainment 5 ปีที่แล้ว

      also 1/2 * 2/3 * ... * (n+1)/n = (n + 1)/1 = n + 1 which isnt equal to n?
      EDIT: think it was supposed to be (n+1)^z on the LHS,
      EDIT 2: gotta finish the vid another time, gotta go to bed

  • @bobthecob8501
    @bobthecob8501 5 ปีที่แล้ว +6

    SHOT CLOCK CHEESE!!!

    • @amartya-w3i
      @amartya-w3i 5 ปีที่แล้ว

      Wtf does that mean

    • @bobthecob8501
      @bobthecob8501 5 ปีที่แล้ว +1

      beta slay My left stroke just went viral

    • @bobthecob8501
      @bobthecob8501 5 ปีที่แล้ว +1

      Marko Rezic Right stroke put lil' baby in a spiral

  • @chandranisahanone
    @chandranisahanone ปีที่แล้ว

    Euler Smells like a GOD🗿🗿🗿🖤🖤🖤

  • @danielcastillo2299
    @danielcastillo2299 5 ปีที่แล้ว

    You’re building up to something, I know it.

  • @duncanw9901
    @duncanw9901 5 ปีที่แล้ว

    OOF for the first time I gotta get a pen and paper and try it myself to be convinced it really works :(

  • @meenar5826
    @meenar5826 5 ปีที่แล้ว

    Bro how e to the power -x is 1-x/n to the power n

    • @TheFireBrozTFB
      @TheFireBrozTFB 2 ปีที่แล้ว

      Thats basically the definition of e
      do the limit of (1+1/n^)^n n--> infinity and youd get e
      it is very famous and you could see the proof online

  • @正大光明-h2p
    @正大光明-h2p 5 ปีที่แล้ว

    我看看这个视频到底能不能让我彻底攻克gamma function

  • @trumanburbank6899
    @trumanburbank6899 5 ปีที่แล้ว +1

    On a related note: If you define,
    P(x) = integral Γ(x)dx
    then integrate P(x+1) by parts, you get
    integral P(x) dx = xP (x) − P (x + 1)
    All succeeding integrals of P(x) are also algebraic, as are polynomial forms, for example the all integrals of the polynomial
    sum(m,n)[x^m P^n(x)]
    can be expressed as a polynomial of a similar form.
    The same is true if you define
    Q(x) = integral (1/Γ(x))dx. As you know, 1/Γ(x) is well-behaved.
    The only thing is, that I don't know what use these functions have.

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    SHOT CLOCK CHEESE

  • @robertmunga2630
    @robertmunga2630 5 ปีที่แล้ว

    Some geometric insight please. Please.

  • @Павел-и5б3ц
    @Павел-и5б3ц 11 หลายเดือนก่อน

    Класс. Спасибо

  • @tiempoluna1482
    @tiempoluna1482 5 ปีที่แล้ว

    La matemática es independiente del idioma.

  • @mihaipuiu6231
    @mihaipuiu6231 7 หลายเดือนก่อน +1

    For me something is wrong in factorial proof! Sorry!

  • @alissonmelisaruiz6608
    @alissonmelisaruiz6608 5 ปีที่แล้ว

    Te amuuuuuuuuuuuuu

  • @正大光明-h2p
    @正大光明-h2p 5 ปีที่แล้ว

    老子还是没懂

  • @evanev7
    @evanev7 5 ปีที่แล้ว

    Spicy

  • @nikolaalfredi3025
    @nikolaalfredi3025 5 ปีที่แล้ว +1

    Last part i.e when you just changed the form of n^z and prdouct of (z+1)(z+2)...(z+n) is not so clear.
    Also, you must try to be somewhat official....(use good language).

  • @kwirny
    @kwirny 5 ปีที่แล้ว

    You talk german? I mean you kind of sound like one.

    • @kwirny
      @kwirny 5 ปีที่แล้ว

      @@PapaFlammy69 Ich wusste es, auf welcher Uni bist du?

    • @kwirny
      @kwirny 5 ปีที่แล้ว

      @@PapaFlammy69 Ich kann mich nicht entscheiden, Bonn oder Aachen. Will im Wintersemester anfangen.

    • @TheAnbyrley
      @TheAnbyrley 5 ปีที่แล้ว

      @@PapaFlammy69 SUNY Potsdam? :-P

    • @kwirny
      @kwirny 5 ปีที่แล้ว

      Ist Bonn geworden :), viel zu tun aufjedenfall.

  • @santiagoalvarez622
    @santiagoalvarez622 4 ปีที่แล้ว

    too bad

  • @GandhiGuru503
    @GandhiGuru503 5 ปีที่แล้ว +6

    SHOT CLOCK CHEESE!!!

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    SHOT CLOCK CHEESE

  • @BobBob-ym1vs
    @BobBob-ym1vs 5 ปีที่แล้ว +6

    SHOT CLOCK CHEESE!!!

    • @markorezic3131
      @markorezic3131 5 ปีที่แล้ว

      If I had a nickel for every time I read this today, I would have 5 nickels, just enough to afford the life of people who write that shit

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    SHOT CLOCK CHEESE

  • @noelabdon4145
    @noelabdon4145 5 ปีที่แล้ว +7

    SHOT CLOCK CHEESE!!!

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    SHOT CLOCK CHEESE

  • @OtiumAbscondita
    @OtiumAbscondita 5 ปีที่แล้ว +1

    SHOT CLOCK CHEESE