can you evaluate this crazy integral??

แชร์
ฝัง
  • เผยแพร่เมื่อ 1 ธ.ค. 2024

ความคิดเห็น • 21

  • @gael8828
    @gael8828 23 ชั่วโมงที่ผ่านมา +29

    Wait, after the t substitution, the argument inside the arctan is wrong. Should be (t^2-4)/2sqrt(2)

    • @jzim5426
      @jzim5426 23 ชั่วโมงที่ผ่านมา +6

      I think so too. The expression for dx is wrong also: The factor 4 should be 1. But this did not change the result because it was canceled out by a missing factor of 4 when substituting the denominator.

    • @cyanide7833
      @cyanide7833 19 ชั่วโมงที่ผ่านมา +1

      yep, due to this i thought there was no way that the final answer could be correct, wolfram alpha approximated the integral to 2.26 however the value to (pi)ln(1+sqrt(2)) is approximately 2.76

  • @rublade1
    @rublade1 23 ชั่วโมงที่ผ่านมา +9

    Wolframalpha gives approx. 2.26 for the integral. The endresult Pi * ln(1 + sqrt(2)) is approx 2.76.

    • @dodgsonlluis
      @dodgsonlluis 21 ชั่วโมงที่ผ่านมา +4

      There is an error at 5:43 into the arctan argument, already noted in a commentary, that flaws completely the result.

  • @inigovera-fajardousategui3246
    @inigovera-fajardousategui3246 22 ชั่วโมงที่ผ่านมา +7

    Shouldn't the derivative at 4:39 be the other way around [√(4-x)-√x]/[2√x(4-x)]? And also, there shouldn't be a 4 in the denominator at 5:01

  • @cyanide7833
    @cyanide7833 19 ชั่วโมงที่ผ่านมา +3

    So when do i stop

  • @bjornfeuerbacher5514
    @bjornfeuerbacher5514 22 ชั่วโมงที่ผ่านมา +3

    I don't get the step at 4:50... how does he arrive at sqrt(8-t²) ?

    • @minamagdy4126
      @minamagdy4126 19 ชั่วโมงที่ผ่านมา +2

      If you compute t²-8, you get (from the computed t²-4)
      2sqrt(x(4-x)) - 4 = -x + 2sqrt(x(4-x)) - (4-x)
      = -(sqrt(x) - sqrt(4-x))²
      Simplifying this yields sqrt(8-t²) = sqrt(x) - sqrt(4-x)
      EDIT: corrected some typos

    • @bjornfeuerbacher5514
      @bjornfeuerbacher5514 19 ชั่วโมงที่ผ่านมา

      @@minamagdy4126 Thanks, I only got the first step and then wondered how to go on from there...

  • @ChuffingNorah
    @ChuffingNorah 17 ชั่วโมงที่ผ่านมา +2

    Is there any physical model for this abstruse, arcane, arctan integral? It's a bit like String Theory being completely dissassociated from any testable real world physics? Maths done for the sake of doing Maths only!

  • @orionspur
    @orionspur 23 ชั่วโมงที่ผ่านมา +2

    Noplace to stop!

  • @ferenc_l
    @ferenc_l 22 ชั่วโมงที่ผ่านมา +1

    Crazy integral from Azerbaijan

  • @BikeArea
    @BikeArea 23 ชั่วโมงที่ผ่านมา +1

    When backflip? 👀✌️

    • @roberttelarket4934
      @roberttelarket4934 22 ชั่วโมงที่ผ่านมา

      The back flip done when he goes "back" from arctan to its inverse tan.

  • @alquinn8576
    @alquinn8576 22 ชั่วโมงที่ผ่านมา +1

    the way u draw square root signs gives me so much frustrage

  • @johntse5770
    @johntse5770 23 ชั่วโมงที่ผ่านมา

    am i third?

  • @Alan-zf2tt
    @Alan-zf2tt 23 ชั่วโมงที่ผ่านมา +1

    First 🌟

    • @BikeArea
      @BikeArea 23 ชั่วโมงที่ผ่านมา +1

      Nope. 😊

    • @Alan-zf2tt
      @Alan-zf2tt 21 ชั่วโมงที่ผ่านมา

      @@BikeArea you mus be in a later time zone no?

  • @DavidWang-v7u
    @DavidWang-v7u 14 ชั่วโมงที่ผ่านมา

    Mike, you are one of the very few people that I know that still does maths channels on TH-cam. Since you can make measurements based on the fact that Paleolithic and Neolithic Chinese People having Multiple Cradles as their Civilizational and Mathematical and Sciences Developmental Theories, the Mathematics based on Counting, like Whole Numbers and Real Numbers, most stuff that should diverge and should be sprung out of Humanities should be discussed, and whether or not those mathematics could be considered to have undergone any significant procedures or have been debunked, ranging from Vector Calculus, Number Theory, etc. etc. and also, those maths should also should not be deceived to be Whole Numbers or Integers so that they do not require critical thinking. The only problem is whether or not the other maths that do not coalign with these mathematics are able to lunge forward, destroy these maths as being mere Humanities Sciences, and able to contribute to the economies, or not..