Proving a Sequence Converges with the Formal Definition Advanced Calculus

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  • Опубліковано 24 гру 2024

КОМЕНТАРІ • 105

  • @thomasyassmin715
    @thomasyassmin715 4 роки тому +40

    Cannot stress how helpful this was ! Been struggling to wrap my head around this, and now it makes so much sense!

  • @RellowMinecraftJourney
    @RellowMinecraftJourney 8 місяців тому +2

    This guy is saving lives.

  • @enes1565
    @enes1565 6 років тому +42

    we need more complicated sequences Amigo..

  • @willdingwall8503
    @willdingwall8503 5 років тому +11

    THANK YOU. I've been struggling with this for weeks. I understand it now at last.

  • @nathanellul5787
    @nathanellul5787 4 роки тому +6

    about 1.5 yrs later and still a great explanation. Cheers!

  • @PunmasterSTP
    @PunmasterSTP Рік тому +1

    Proving a sequence converges? More like "Phenomenal video with great information for us!"

  • @laytion4585
    @laytion4585 3 роки тому +4

    3:03 may I ask why is it that we're able to insert another equation in between and use that one instead?
    edit: (my thinking), by an equation larger than the original one, wouldn't its N also be larger? and shouldn't we find the lowest possible N?

  • @observever7808
    @observever7808 4 роки тому +6

    Although there's lack of theory, this method of proving and justification is easy to understand!

    • @Karim-nq1be
      @Karim-nq1be Рік тому +3

      There's "lack of theory" because the goal in this case is to apply theory to solve a specific case.

  • @MrPog09
    @MrPog09 Рік тому

    You're really a maths wizard fr, thanks for saving my grades.

  • @myreflection287
    @myreflection287 4 роки тому +10

    Thank you so much! Been so stressed out with online classes! Super helpful!

  • @Kaleraa
    @Kaleraa 4 роки тому +24

    So.... I'm new here but.... is no one gonna talk about the rat?

  • @kristenchou
    @kristenchou 6 років тому +4

    Sandwich theorem:
    Lim(n+1)/(n+1) -> 1 as n -> infinity.
    Lim(n-1)/(n+1) -> 1 as n-> infinity.
    (n-1)/(n+1) < n/(n+1) < 1
    Hence lim n/(n+1) -> infinity as n -> infinity

    • @TheMathSorcerer
      @TheMathSorcerer  6 років тому +1

      i think you typoed at the end, should be ->1,but very clever way of doing this, awesome, thanks for sharing, I don't think I've ever seen it done this particular way:)

    • @kristenchou
      @kristenchou 6 років тому +1

      @@TheMathSorcerer oops yes youre right haha!

  • @RellowMinecraftJourney
    @RellowMinecraftJourney 8 місяців тому

    I am
    writing tomorrow and this was the concept i was confused about until no, Thank you very much.

  • @Or0203
    @Or0203 4 роки тому +2

    love it when little n is bigger than big n

  • @AnjaliSharma06
    @AnjaliSharma06 4 роки тому +3

    your explanation is amazing, thanks a ton!!!

  • @SeeTv.
    @SeeTv. 3 роки тому +1

    Amazing video! Very understandable

  • @killuaenthusiast
    @killuaenthusiast 3 роки тому +2

    Thank you, sir. Incredible explanation.

  • @hellman108
    @hellman108 5 років тому +7

    This a super solid explanation. Thank you

  • @ruries4240
    @ruries4240 Рік тому

    Cant I say 1/n +1 is less than epsilon? Because when u simplify the original modulus expression it gives u 1/n +1?

  • @xxrawrgameremo98xx86
    @xxrawrgameremo98xx86 3 роки тому +2

    You've been carrying my mark through university. Thank you for the great vids :)

  • @erikagarfias8731
    @erikagarfias8731 4 роки тому +1

    For proving the sequence converges with the formal definition, how would we know when to stop, would be when we reach 1/n in general or varies by each question?

  • @deborahodion5240
    @deborahodion5240 3 роки тому +1

    Finally understand this.
    Thanks

  • @zahinahmed4216
    @zahinahmed4216 4 роки тому +4

    nice video ...but i have a confusion...why 1/(n+1)

    • @TheMathSorcerer
      @TheMathSorcerer  4 роки тому +1

      Because n +1 is bigger than n so the fraction on the left is smaller

  • @hiranmaimohan3399
    @hiranmaimohan3399 4 роки тому +2

    Great explanation !!!

  • @gisellabradley7270
    @gisellabradley7270 5 років тому +3

    Would it be the same proof if the denominator is n+2 or n+3?

  • @bodozeidler9118
    @bodozeidler9118 4 роки тому

    But why is a convergent sum like 1/n regarded as =1, although it never becomes 1 ? Is it by Definition regarded as 1? Or is it a believe that it becomes 1 by Infinite procedure?

  • @mo8046
    @mo8046 3 роки тому

    What would go wrong if I tried to prove that the limit converges to any number other than 1? What would go wrong if I tried to prove that it converges to 2?

  • @akinyimildred6012
    @akinyimildred6012 2 роки тому +1

    Good work😃

  • @justinernest2363
    @justinernest2363 Рік тому

    how were you supposed to know that you had to make 1/n+1

  • @Jade-sv6mz
    @Jade-sv6mz 2 роки тому +1

    you just saved my life

  • @tarekzoabi9031
    @tarekzoabi9031 4 роки тому

    Is having the actual value of the limit necessary to be able to prove it's existence? I mean can you prove the existence of the limit _before_ finding it's numerical value?

  • @ckeimel
    @ckeimel 4 роки тому +1

    thank you so much. I was stuck with the first exercise. Now I begin to understand how to do it.

  • @huntermaxfield5642
    @huntermaxfield5642 5 років тому +1

    great video for explaining the procedure and intuition behind the proof. thanks.

  • @aidandizaji8876
    @aidandizaji8876 2 місяці тому

    very informative video, thank you

  • @youngzuczek344
    @youngzuczek344 Рік тому

    Why did you switch from 1/n+1 to 1/n ?

  • @32_gurjotsingh82
    @32_gurjotsingh82 4 роки тому +1

    thanks i was really strulggling to find the exact wordings to explain that formal defination..iin order to imagine clearly....

  • @kingsykes7597
    @kingsykes7597 4 роки тому +5

    haha my question is how you making this seem simple and interesting...THANK YOU SO MUCH for the help

  • @ivanlo7195
    @ivanlo7195 2 роки тому

    I might feel something might not logically correct in the scratch work, the statement
    (1/n+1)

  • @ajitasingh6597
    @ajitasingh6597 4 роки тому +1

    It was very amazing...I always wondered what is the use of m and then m greater than 1/epsilon....now it's almost clear

  • @issam2901
    @issam2901 5 років тому +1

    Suppose you didn't use the fact that 1/(n+1) < 1/n then you would find n > 1/ε - 1. It will yield the same result at the end. My question is why did you use 1/n > 1/n+1 ? It seems unnecessary. And i am asking this because i have seen this proof in many textbooks done the same way you did it. Am i missing something ?

    • @TheMathSorcerer
      @TheMathSorcerer  5 років тому +1

      no you are not, it's just that , I think that n > 1/e is cleaner than n >1/e - 1. You could CERTAINLY do it that way, there is nothing wrong with that, you could say you are ch oosing an integer n such that n > 1/e - 1 via the archimedean property and it's all ok

  • @hmasters8538
    @hmasters8538 2 роки тому

    sir, how about capital N ??do we just ignore it when we write the final answer? or we can choose both weather ignore or write it?

  • @maxsmith8474
    @maxsmith8474 3 роки тому

    This was the video where it clicked, ty

  • @NoName-jh7yj
    @NoName-jh7yj 4 роки тому +2

    Why is 1/(n+1)

    • @TheMathSorcerer
      @TheMathSorcerer  4 роки тому +3

      never:) I just used

    • @NoName-jh7yj
      @NoName-jh7yj 4 роки тому

      @@TheMathSorcerer ok, thank you very much

    • @NoName-jh7yj
      @NoName-jh7yj 4 роки тому +1

      @@TheMathSorcerer I'm actually struggling a bit. I have no idea how to apply the same method for a limit like this:
      (-1)^n/(5n-2) = 0

  • @dangerousangel777
    @dangerousangel777 4 роки тому

    At 3:10....How do you know that 1/n is less that epsilon? Since at 4:58 you said we can't just write |(n/n+1)-1| < ε ...please explain this to me....and what does everyone mean when they say they can "choose" epsilon?

    • @TheMathSorcerer
      @TheMathSorcerer  4 роки тому +1

      because we are figuring it out(it's the scratchwork, so we can do anything), in the proof, the 2nd part, we have to formally show it:)
      Sometimes people say choose e>0, but really,it's N that we choose. In these proofs we have to find N.
      I will upload more of these soon. It's a tough topic!!!
      BTW the reason we can choose N is because of the Archimedean Principle, it says given any number c, we can find a natural number N that is bigger than c. So in this example we chose N > 1/e

  • @captain7039
    @captain7039 4 роки тому +2

    👍🏻 easily understandable video👌 ,we want more examples.

  • @1971kitcha
    @1971kitcha 4 роки тому

    whether calculus is related to binomial theorm?

  • @Charjallz
    @Charjallz 5 років тому +2

    You explained this very well, and in a fun way! I always get stuck on proofs.
    Does this show it converges then? And do you have any videos that explain what it means? Thanks!

    • @TheMathSorcerer
      @TheMathSorcerer  5 років тому +2

      ya it shows it converges, yeah check my advanced calculus playlist for other convergence proofs, basically it means that when n gets really really big, n/(n + 1) gets really really close to 1:)

    • @TheMathSorcerer
      @TheMathSorcerer  5 років тому +2

      so if we let n go to infinity and we get a number, then we say the limit exists, it is the number, in this case 1, and the sequence n/(n + 1) converges to 1

  • @ntvonline9480
    @ntvonline9480 4 роки тому +1

    Why do you have to show every step of your simplifying? Why can't you jump from the definition of convergence to (1/n)? (Trying to save some pencil lead) :D

  • @dabisax2536
    @dabisax2536 5 років тому

    Why did you subtract two from the denominator and conclud epsilon is greater than the value .

  • @1971kitcha
    @1971kitcha 4 роки тому +3

    I'm reading the mathematical proofs by Gary Chartrand, which is ur prescribed book for proofs,
    and I have gone through this problem at 307 th page

  • @turokg1578
    @turokg1578 Рік тому

    how to show sequences like (1/n,n/(n+1))?

    • @turokg1578
      @turokg1578 Рік тому

      he literally has a video on that. in case some1 else is searching for it here it is:
      ua-cam.com/video/B5rqQtp-LIQ/v-deo.html

  • @MegaLovehope
    @MegaLovehope 4 роки тому +1

    You are the best !!!

  • @dinirahmawati4257
    @dinirahmawati4257 4 роки тому +1

    Thank you it helps a lot

  • @ericw2859
    @ericw2859 4 роки тому +1

    you save my life thankyou

  • @heathrobertson2405
    @heathrobertson2405 Рік тому

    Thank you very helpful!

  • @IntegratingIntoSoceity
    @IntegratingIntoSoceity 10 місяців тому

    All hail the rat puppet; the only thing carrying me through Calc this year 😩🙏

  • @hidbulbzrus
    @hidbulbzrus 2 місяці тому

    my teacher almost always uses N interchangeably for integers. Like why why why... and he wrote his own textbook rather than using something excellent like Cummings or Buck.

  • @hanskywalker1246
    @hanskywalker1246 Рік тому

    I don't understand why we need n and N, where's the difference ?

  • @aqueeqazam
    @aqueeqazam 5 років тому +2

    Wow sir👍.

  • @andrewadams4982
    @andrewadams4982 5 років тому +1

    This is helpful, thanks a lot!

  • @alisondunning2446
    @alisondunning2446 4 роки тому

    Great explanation! One part I got confused on though, why exactly did you need to apply the Archimedean principle and choose an N greater than 1/ε? Couldn't you just keep N = 1/ε, since we're going to end up with the n being greater than 1/ε anyway? Is this because we want N to be a positive integer, and if ε ∉ Z+, we will just have 1/ε ∉ Z+?

    • @TheMathSorcerer
      @TheMathSorcerer  4 роки тому +1

      right we want N to be a positive integer, that's why

  • @askmargo
    @askmargo 4 роки тому

    Thank you thank you thank you 🙌🏻

  • @KonstantinKrasser
    @KonstantinKrasser Рік тому

    Amazing!

  • @kneazleje
    @kneazleje 3 роки тому

    thank you

  • @mpandejonasshane
    @mpandejonasshane 3 місяці тому

    Im so stressed over mathematical analysis 1 that I'm currently doing 😢,, anyways Thanks alot atleast I'm catching up ,,

  • @LOVE_SHAYARI_420
    @LOVE_SHAYARI_420 4 роки тому +1

    Thanks sir

  • @jamesclerkmaxwell676
    @jamesclerkmaxwell676 4 роки тому +1

    Nice !

  • @quant-prep2843
    @quant-prep2843 3 роки тому

    god sent

  • @kumaripooja6351
    @kumaripooja6351 8 місяців тому

    Kuchh samjh nhi aaya