a surprisingly interesting sum -- 2 ways!

Поділитися
Вставка
  • Опубліковано 28 лис 2024

КОМЕНТАРІ • 38

  • @xizar0rg
    @xizar0rg Рік тому +148

    Starting off saying he's going to use "one of my favorite functions", I was confused as to how the floor function was going to come into play.

    • @MichaelGrantPhD
      @MichaelGrantPhD Рік тому +8

      I saw your comment before I hit start, so I was waiting for him to say this... but then he said "one of my favorite *special* functions" and I knew he meant something different. Because why the floor function is indeed awesome, I knew it wasn't "special" in the mathematical sense of the term!

    • @wesleydeng71
      @wesleydeng71 Рік тому +2

      Generating function is another one of his. I can attest to that.

    • @Ahmed-Youcef1959
      @Ahmed-Youcef1959 Рік тому

      @@wesleydeng71
      Sure ,i was waiting for Generating function

  • @JohnSmith-zq9mo
    @JohnSmith-zq9mo Рік тому +18

    For the interchange of integration and summation, the monotone convergence theorem can also be used since everything is positive.

  • @PhilBoswell
    @PhilBoswell Рік тому +28

    It is super interesting to see how Michael adjusts his approach as he goes, but also super confusing when he suddenly rewinds without warning.
    Would it be possible, even if slightly janky, to insert a "rewind" effect to demonstrate that the backwards jumps are deliberate rather than an editing error?

    • @UltraMaXAtAXX
      @UltraMaXAtAXX Рік тому +6

      It would be so on brand with the humor of Stephanie - make it happen, please?

  • @goodplacetostop2973
    @goodplacetostop2973 Рік тому +13

    13:27

  • @عمرانآلعمران-و7خ

    Here is a another approach to the second way , notice that the integral of dilog(x) from 0 to 1 = the integral of dilog(1-x) form 0 to 1 and use the remarkable identitiy dilog(x)+dilog(1-x)+ log(x) log(1-x)=zeta(2) so it suffices to evaluate the integral of log(x)log(1-x) from 0 to 1 , this can be easily calculated by using a little trick.

  • @jonathanbeeson8614
    @jonathanbeeson8614 Рік тому +15

    Interesting and instructive problem and solutions as usual, Professor Penn, but it seems there were some problems with the editing today...a couple of redundant bits left in possibly by mistake.

  • @adandap
    @adandap Рік тому +1

    Christmas time at Michael's place. "Help yourself to a nut. There's a nutcracker there, or you can use one of my favourite tools - that steamroller outside."

  • @manucitomx
    @manucitomx Рік тому +1

    That was very cool!
    Thank you, professor!

  • @HerbertLandei
    @HerbertLandei Рік тому +1

    Great, now do the same for sum 1/n³

  • @paulkohl9267
    @paulkohl9267 Рік тому +1

    Thank you MP for doing so many great math vids!

  • @martinkausoh1386
    @martinkausoh1386 Рік тому +4

    Some problem with the video cutting? Thatś the second time that I noticed a start-over in between😊

  • @redroach401
    @redroach401 6 місяців тому

    This was my favourite explanation of new bounds thank you so much

  • @oddlyspecificmath
    @oddlyspecificmath Рік тому +3

    This was fun; I've been looking for perspective on sums and (for me at least) this has just the right level of progression to help me pause and analyze what's familiar to others. Thanks 😊

  • @Calcprof
    @Calcprof Рік тому

    Partial fractions is actually not a theorem about integration, but rather a theorem about the structure of rational functions. As such it comes up in many areas.

  • @martinkausoh1386
    @martinkausoh1386 Рік тому +1

    Great to see my favorite math professor at large but I prefer the first solution 😅 Many thanks Michael for Your hard and inspiring work

  • @CielMC
    @CielMC Рік тому

    The video was a little jumpy, but the ride was enjoyable.

  • @holyshit922
    @holyshit922 Рік тому +1

    What about following sum
    sum((n choose 2m)(m choose k),m=k..floor(n/2))
    Result should depend on n and k
    Wolfram Alpha does not calculate this sum correctly

  • @RUKA-ur6oj
    @RUKA-ur6oj Рік тому

    分かりやすいです

    • @MrMctastics
      @MrMctastics Рік тому +1

      But it's in English though 😂

  • @puertavideo
    @puertavideo Рік тому +8

    5:58 - 6:04 ?? Is that ment to be there

    • @woody442
      @woody442 Рік тому +5

      Absolutely! It was a little spoiler in case you were about losing attention ;-)

    • @txikitofandango
      @txikitofandango Рік тому +1

      Harkens back to when he used to edit his own videos :)

    • @robertveith6383
      @robertveith6383 Рік тому

      * meant

  • @petersievert6830
    @petersievert6830 Рік тому

    Some heave time travelling this time around ;-)

  • @y.k.495
    @y.k.495 Рік тому +5

    it's looks like ζ(2)+ζ(3) !

  • @Patapom3
    @Patapom3 Рік тому

    Amazing!

  • @CM63_France
    @CM63_France Рік тому

    Hi,
    And so, compared to the sum of the inverses of the squares, it only subtracts 1? not very glorious 😆
    Editing problems.

  • @moulinaie
    @moulinaie Рік тому +1

    I'm happy I got the solution ! This is not so easy on this channel !! Thanks for your cool problems.

  • @konstantintrifonov7319
    @konstantintrifonov7319 Рік тому +1

    I recently saw a similar video about calculating using the integral of the dilogarithm ua-cam.com/video/pmuFPRiNgjc/v-deo.html

  • @Alluminum-z6n
    @Alluminum-z6n Рік тому +1

    I pushed the 2^8th like

  • @zlodevil426
    @zlodevil426 Рік тому +1

    there was no need to bring this horrible calculus into a simple problem

  • @franksaved3893
    @franksaved3893 Рік тому +3

    Michael's favorite trick is fucking awesome

    • @robertveith6383
      @robertveith6383 Рік тому

      Stop your major cursing, especially in a mathematics forum. It is rude, ignorant, and needless.