Series of (1+1/n)^(n^2), root test

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  • เผยแพร่เมื่อ 24 ม.ค. 2025

ความคิดเห็น • 25

  • @MichaelCMartinez
    @MichaelCMartinez 2 ปีที่แล้ว +2

    You are amazing at explaining and it's a joy to watch you solve these advanced problems with a smile on your face. Cheers to you friend!!

  • @jamesfowler9405
    @jamesfowler9405 6 ปีที่แล้ว +9

    Nice video! Also digging the death star microphone.

  • @ffggddss
    @ffggddss 7 ปีที่แล้ว +5

    Not only does the sum diverge; the *sequence* diverges!
    Just look at the first two terms of the binomial expansion (all of whose terms are positive here, so the whole thing is greater than the first two terms).
    (1 + 1/n)^n² = 1 + n²/n + ... = 1 + n + ...
    and as n→∞, ... well, you get the picture.

  • @KlasseCaldiny
    @KlasseCaldiny 3 ปีที่แล้ว +4

    I'm confused by this. As n approaches infinity for (1+1/n)^n, the inside of parenthesis will just be (1+0)^n, so it will be 1. How did it become 'e' ???!?

    • @KlasseCaldiny
      @KlasseCaldiny 3 ปีที่แล้ว +4

      nvm working it out. I forgot 1^infinity is indeterminate and have to use L'hopital. watching 'the fact' video now.

  • @tumininuadeeko6494
    @tumininuadeeko6494 5 ปีที่แล้ว +27

    How did it become e??

    • @dhanurgarg9988
      @dhanurgarg9988 3 ปีที่แล้ว +2

      Because when u put limit n tends to infinity we get 1^infinity which is indeterminate form and u have to use natural log to solve it

  • @kiran9528
    @kiran9528 5 ปีที่แล้ว +6

    What if it's raised to n^3 not n^2

  • @stephenbeck7222
    @stephenbeck7222 7 ปีที่แล้ว +3

    Why does Test for Divergence (nth term test) not work on this series? The inside part, 1 + 1/n, is always greater than 1, and the exponent n^2 is always greater than 1, therefore the whole term is greater than 1, and thus the limit is not 0. I believe using "the fact" the limit is actually e^n ≠ 0.

    • @blackpenredpen
      @blackpenredpen  7 ปีที่แล้ว

      Stephen Beck hmm did I say TFD doesn't work for this vid? I don't remember. In fact u could. The lim of a_n does go to inf thus the series div by TFD.

    • @stephenbeck7222
      @stephenbeck7222 7 ปีที่แล้ว

      I believe you were referring to this video when you tried the root test on the other one and switched to TFD.

  • @prasanjithlorensuhewa6689
    @prasanjithlorensuhewa6689 3 ปีที่แล้ว +1

    Using the L'Hopitals rule we can prove that.

  • @markgraham2312
    @markgraham2312 4 ปีที่แล้ว +3

    lim n->infinity (1 + 1/n)^2 =e because of THE FACT!

    • @DRACOBUCIO
      @DRACOBUCIO 3 ปีที่แล้ว

      You are wrong, instead of (1 + 1/n)^2 is :(1 + 1/n)^n

  • @ahitch3681
    @ahitch3681 5 ปีที่แล้ว +1

    is because you can do natural log and manipulate the exponent down?

  • @UniquelyUzz
    @UniquelyUzz 3 หลายเดือนก่อน

    What to do if we get 1

  • @elomargalib
    @elomargalib 2 ปีที่แล้ว

    What is the sum of √(1+((2r-1)/n)²) where n = infinity and r=1 to n

  • @ehclipse8764
    @ehclipse8764 3 ปีที่แล้ว +2

    So anyone want to explain to me why this approaches e? Besides graphing it

  • @sanwellbeatz1630
    @sanwellbeatz1630 3 ปีที่แล้ว

    Donno if its a stupid question but ,what is he holding in his hand?

    • @Shredrex
      @Shredrex ปีที่แล้ว

      a microphone

  • @AndDiracisHisProphet
    @AndDiracisHisProphet 7 ปีที่แล้ว +4

    Because of the "fact" ;D

  • @bhargava730
    @bhargava730 2 ปีที่แล้ว

    Thank u sir

  • @hunggarchristian
    @hunggarchristian 6 ปีที่แล้ว +3

    Thanks man

  • @giovannastopa9522
    @giovannastopa9522 ปีที่แล้ว

    👏🏼🫶🏼