A monster double integral from the romanian mathematical magazine

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  • Опубликовано: 2 авг 2023
  • The 2 log integrals designed to give you a scare before scooby the contour doo bee doo unmasked them as pi:
    • A wonderful applicatio...
    The second ever RMM integral I've solved here on the channel and the solution development was indeed epic!

Комментарии • 45

  • @ankushparcha5722
    @ankushparcha5722 11 месяцев назад +7

    That was mine problem
    ❣️Thank you❣️for sharing such✨👏 nice solution ✨👏

    • @maths_505
      @maths_505  11 месяцев назад +2

      You mean you're the one who presented it to the RMM?

    • @maths_505
      @maths_505  11 месяцев назад +1

      That is so awesome!!!
      Feels like I'm talking to a celebrity 😂🥳!!!
      A subscriber emailed me this integral asking if I could solve it.... nd I must say it's a beautiful integration problem with those 2 log integrals needing a video of their own where I had to use contour integration.

    • @maths_505
      @maths_505  11 месяцев назад +2

      Thank you for creating such a beautiful monster integral

    • @ankushparcha5722
      @ankushparcha5722 11 месяцев назад

      ​@@maths_505yes!!

    • @ankushparcha5722
      @ankushparcha5722 11 месяцев назад +1

      ​@@maths_505🙏Thank you 🙏 ✨that's your sublimity ✨and 🙏thank you 🙏 for such❣️ lovely words ❣️, really it ✨made my day ✨

  • @eu7059
    @eu7059 11 месяцев назад +33

    Finally an integral in which γ doesn’t suddenly disappear at the end, I always feel bad for my boy macaroni not being invited to the party every time

    • @maths_505
      @maths_505  11 месяцев назад +6

      I feel the same whenever I see \gamma terms cancelling out of nowhere

  • @user-tn4qe9ne9j
    @user-tn4qe9ne9j 11 месяцев назад +3

    Both of the integrals containing log(1+x^2) can be solved without contour integration. The first in particular is elementary.

    • @edgarwang4659
      @edgarwang4659 7 месяцев назад

      it's actually quite nice! use feynman's trick on ln(1+sx^2)/x^2 and the first one is quite clear. when you tack on an extra ln x, you do the same steps until you eventually get to integrate 0 to inf ln(t)/(1+t^2) dt which is equal to 0 by the usual t = tan theta substitution

  • @marcosjuniorquijadagonzale9778
    @marcosjuniorquijadagonzale9778 11 месяцев назад +1

    Excellent double integral 🔥

  • @IndranilBiswas_
    @IndranilBiswas_ 11 месяцев назад +4

    Something about Eastern Europe and math ❤️❤️❤️💯💯💯

  • @MrWael1970
    @MrWael1970 11 месяцев назад

    Very smart solution. Thank you.

  • @manstuckinabox3679
    @manstuckinabox3679 11 месяцев назад +1

    LOL forgot you fix x as a constant inside the first integral. extremely nice result my friend.

  • @enzojorge1459
    @enzojorge1459 11 месяцев назад +1

    you cant write ln(xu) as ln(x) + ln(u) and then separate the integrals in 2 integrals since you don't even know if the new integrals are well defined.
    it's like saying that the integral from 0 to infinity of 0 is the integral of x - x is the integral of x - the integral of -x, you have inf-inf

  • @HM-cw8im
    @HM-cw8im 11 месяцев назад

    Amazing! Where can I learn more about the Gamma function's properties and the constant that popped up in the end?

    • @maths_505
      @maths_505  11 месяцев назад

      Scattered all over the channel 😂

  • @dvdtsb
    @dvdtsb 11 месяцев назад +3

    im romanian! yeah rmm is wild sometimes

    • @maths_505
      @maths_505  11 месяцев назад +3

      I've got a few more in my notes that I'll upload soon

    • @ngc-fo5te
      @ngc-fo5te 11 месяцев назад

      ​@maths_505 Be careful - RMM often publishes incorrect solutions. There was a good example of this on MSE recently where the published solution derivation was incorrect in the first line and the rest was thus garbage.

    • @maths_505
      @maths_505  11 месяцев назад +1

      @@ngc-fo5te interesting. Thankfully I prefer coming up with my own solutions and then cross check the final answer with wolfram alpha.

    • @maths_505
      @maths_505  11 месяцев назад +3

      @@ngc-fo5te funny thing is when I mess something up and retrace my steps I often realize that I've evaluated a new integral altogether 😂😂😂

  • @insouciantFox
    @insouciantFox 11 месяцев назад +1

    And don't call me Shirley

  • @danielrosado3213
    @danielrosado3213 11 месяцев назад +3

    Hot 🔥

  • @zinzhao8231
    @zinzhao8231 11 месяцев назад

    beautiful

  • @user-mh3vr5rw9r
    @user-mh3vr5rw9r 11 месяцев назад

    Can you solve the integral of :
    ln(sinx+cosx)/(cosx-sinx) dx

  • @user-fh5rm2ef4n
    @user-fh5rm2ef4n 11 месяцев назад +1

    Hey, I'm a bit confused by your Fubini theorem (I assume it's not about measure theory, since you mentioned continuity). But isn't it the case that for double Rieman integrals continuity suffices only when the rectangle (rigeon of integration) is bounded?

    • @maths_505
      @maths_505  11 месяцев назад +1

      It works for the case of improper integrals as well provided the integral converges

    • @user-fh5rm2ef4n
      @user-fh5rm2ef4n 11 месяцев назад

      @maths_505 Just converges or absolutely converges? I haven't looked at those theorems in the case of Rieman integral for a while, but if absolutely converges, then it's merely Fubini theorem for product measure.

    • @maths_505
      @maths_505  11 месяцев назад +1

      @@user-fh5rm2ef4n convergence works just fine

  • @Mosux2007
    @Mosux2007 11 месяцев назад

    How would such an integral ever occur?

  • @anupamamehra6068
    @anupamamehra6068 11 месяцев назад

    Hi math 505 can you suggest some books from where one can study Bsc mathematics?

    • @maths_505
      @maths_505  11 месяцев назад +1

      I think that means calculus 1,2 and 3
      Linear algebra and differential equations.
      Try MIT OCW on RUclips.

    • @anupamamehra6068
      @anupamamehra6068 11 месяцев назад

      thanks a ton

  • @yoav613
    @yoav613 11 месяцев назад +1

    Noice

  • @comdo777
    @comdo777 11 месяцев назад +1

    asnwer=1 isit thank you

  • @averagecornenjoyer6348
    @averagecornenjoyer6348 11 месяцев назад +1

    is it me or you've been developing a lisp

    • @maths_505
      @maths_505  11 месяцев назад +1

      I use adobe podcast to filter out background noises and for some reason it messes up audio at some places to make it sound like I have a lisp. It's pretty annoying for me when I watch my own videos but atleast I'm rid of the background noises. If you've seen my old videos you'll notice lots of background noise and even though I've moved houses and it's pretty quiet in my room, the air conditioning introduces considerable background noise

    • @averagecornenjoyer6348
      @averagecornenjoyer6348 11 месяцев назад

      @@maths_505 i underthtand, i thought you thuddenly developed a lithp and i thought it wath kinda funny