Solution 99: Creatively Juggling Limits, Integrals, and Derivatives

แชร์
ฝัง
  • เผยแพร่เมื่อ 25 ธ.ค. 2024

ความคิดเห็น • 33

  • @CHector1997
    @CHector1997 5 ปีที่แล้ว +5

    I have deleted my old question about uniform convergence because I dont want to distract people with my old doubts. Now I have the complete proof of it, Its Right that there is uniform convergence however it isnt easy to verify it.
    Thanks for all!!

  • @mohammedal-haddad2652
    @mohammedal-haddad2652 5 ปีที่แล้ว +1

    That was very informative. Thank you very much.

  • @padraiggluck2980
    @padraiggluck2980 2 ปีที่แล้ว

    ⭐️

  • @VSevenofV
    @VSevenofV 5 ปีที่แล้ว +1

    I just had a question about the rigor of the argument. The textbook theorem only provides for the existence of limits on the interval for x of (1, inf). Does that not mean it does not follow that the limit replacement method and limit as x -> 0+ has no guarantee to exist? Or is this a reversed flow; the existence of the limit on that interval justifying the substitution? That was the only part that was tough to follow for me. Thanks in advance for any assistance you can provide.

    • @LetsSolveMathProblems
      @LetsSolveMathProblems  5 ปีที่แล้ว +2

      Note that we made a substitution from x to 1/x, so our function AFTER the substitution takes value of x in the interval (0, 1). Thus, taking the limit as x -> 0+ after the substitution is justified.

    • @VSevenofV
      @VSevenofV 5 ปีที่แล้ว +1

      @@LetsSolveMathProblems ah of course it inverts the interval. Thank you! This was truly a brilliant solution to watch.

    • @leif1075
      @leif1075 4 ปีที่แล้ว

      @@LetsSolveMathProblems Do you not agree no one would have thought of this solution if they hadn't seen this theorem or these limits before?? Thanks for sharing and in advance for answering.

  • @l10n919
    @l10n919 5 ปีที่แล้ว

    What's the drawing software you use?

  • @PhoenixMarco5
    @PhoenixMarco5 5 ปีที่แล้ว

    I’m just about to start upper level math. Taking real analysis and abstract algebra this semester. How long before I master problems like these? Is this grad level math or undergrad level? I’m scared I’ll never get to this level...

  • @spiritgoldmember7528
    @spiritgoldmember7528 5 ปีที่แล้ว +16

    Here’s an infinite series suggestion:
    S=1-(1/4)+(1/6)-(1/9)+(1/11)-(1/14)+...

    • @aswinibanerjee6261
      @aswinibanerjee6261 5 ปีที่แล้ว +13

      The answer is integration of (1-x³)/(1-x⁵) from 0 to 1

    • @arthurgames9610
      @arthurgames9610 4 ปีที่แล้ว

      @@aswinibanerjee6261 I have used the cotagent summation representation, getting S=2+(pi/5)cotg(pi/5). Pi/5= 36°. Expanding cotg(36°) you get S=
      (800+pi*sqrt(5000-1000*sqrt(5))+pi*sqrt(200-40*sqrt(5))+pi*sqrt(4000-800*sqrt(5)))/400

    • @arthurgames9610
      @arthurgames9610 4 ปีที่แล้ว

      It's pretty easy, you get
      S=
      (800+pi*sqrt(5000-1000*sqrt(5))+pi*sqrt(200-40*sqrt(5))+pi*sqrt(4000-800*sqrt(5)))/400

  • @shashankkataria6530
    @shashankkataria6530 5 ปีที่แล้ว

    Great problem but how can we assume fn(x) to be uniformly convergent?

  • @佐藤-b9g
    @佐藤-b9g 5 ปีที่แล้ว

    That's beautiful piecewise quadrature.

  • @santoshtripathy7808
    @santoshtripathy7808 5 ปีที่แล้ว +1

    I believe that I used the same Idea(But wasn't able to write it properly due to poor internet connection and my old phone)...

  • @ああ-u3r2u
    @ああ-u3r2u 4 ปีที่แล้ว

    区分求積法は便利ですね

  • @leif1075
    @leif1075 5 ปีที่แล้ว +1

    But who WHO would ever think of doing that step at 6:00..can you please respond and tell me?

    • @arthurgames9610
      @arthurgames9610 4 ปีที่แล้ว +1

      A very inteligent guy

    • @leif1075
      @leif1075 4 ปีที่แล้ว

      @@arthurgames9610 i am and I didn't

    • @arthurgames9610
      @arthurgames9610 4 ปีที่แล้ว +1

      @@leif1075 A very very inteligent guy

    • @leif1075
      @leif1075 4 ปีที่แล้ว

      @@arthurgames9610 i am am and i didnt...must be dumb luck

    • @ZeonLP
      @ZeonLP 4 ปีที่แล้ว +1

      maybe ur not as smart as u think then

  • @yulen8
    @yulen8 3 ปีที่แล้ว

    very easy my friends

  • @sangwookim5551
    @sangwookim5551 5 ปีที่แล้ว +1

    혹시 한국인이세요...?

  • @proto9053
    @proto9053 5 ปีที่แล้ว

    Much easer with abel summation...

    • @CHector1997
      @CHector1997 5 ปีที่แล้ว

      Abel summation is for series... the sequence on the video isnt a series so... ¿can you detail your answer?

  • @leif1075
    @leif1075 5 ปีที่แล้ว

    Does f subscriptt,n mean a function that takes vues n but does NOT mean a function of n, is that correct? Only f(n) means,something is a function of n,correct?

  • @infopek3221
    @infopek3221 5 ปีที่แล้ว

    wat

  • @leif1075
    @leif1075 5 ปีที่แล้ว

    The limit of a product equals,the product,of the limits so x times lnx limit is zero? Why not just do it that way..you get zero times one which is zero ..