Alternating Series, Types of Convergence, and the Ratio Test

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  • Опубліковано 9 лют 2025

КОМЕНТАРІ • 54

  • @c001pers0n
    @c001pers0n 4 роки тому +100

    Kinda funny how you explain concepts better in 12 minutes than multiple hours of lecture from my professor.

    • @carmenouzon6690
      @carmenouzon6690 9 місяців тому

      Actually crazy

    • @carmenouzon6690
      @carmenouzon6690 9 місяців тому

      @@banaanpropaan9344there are proofs on here that are explained in 10 minutes and better than 2 hour explanations

  • @rirhassan6355
    @rirhassan6355 3 роки тому +7

    just to let u know ..u explain much better than my uni professor ....u r so good .........i understood all of it in 12 mins.......

  • @brysonmutinda5280
    @brysonmutinda5280 2 роки тому +15

    Simply the BEST proffesor,you make difficult things simple

    • @random6033
      @random6033 Місяць тому

      or maybe others make simple things difficult

  • @hugoteupel8382
    @hugoteupel8382 11 місяців тому +2

    I’m writing math and physics exams this semester and I can say it’s all self-taught thanks to you😂much love

  • @ahmadsab_
    @ahmadsab_ 28 днів тому

    my professor refuses to give me the references for what we're studying, this video made me explain what i missed in the 4 lectures i was sick and couldnt attend, thanks Dave!

  • @gokuldath6084
    @gokuldath6084 5 років тому +12

    You're the best in the business, thank you

  • @risinglabyrinth5977
    @risinglabyrinth5977 11 місяців тому +1

    You scared me on question four of the comprehension test, you had me thinking I was supposed to tetrate XD! Thanks for these videos Professor Dave, these actually really help and give some intuition on these topics.

  • @rolofiend
    @rolofiend 5 років тому +4

    You're actually a savior. Holy moly.

  • @samirouhani
    @samirouhani 9 місяців тому +1

    Thanks a lot. Just one point, from what I've been studying, I've learned that the AST only tells us whether an alternating series is convergent or not, and it doesn't tell us anything about its divergence.

  • @sameersaifi3300
    @sameersaifi3300 3 місяці тому +2

    I Am from India🇮🇳 I totally understand the topic

  • @allo9228
    @allo9228 6 років тому +12

    Hope you're doing well Professor ☺️

  • @Kiky_MedPhysicist
    @Kiky_MedPhysicist 5 місяців тому

    Thank you sir for your dedication! 🙏

  • @ivowehsely9131
    @ivowehsely9131 Рік тому

    I love you professor Dave!

  • @unknownbeing8222
    @unknownbeing8222 4 роки тому +12

    Im now studying mathematics lol, i never thought i would do this.

    • @demonnogo
      @demonnogo 4 роки тому +4

      Same, lol! I literally have no need or reason to but it's something that I feel compelled to do.

    • @ian.ambrose
      @ian.ambrose 3 роки тому +1

      @@demonnogo You study math just because you feel like so? Woah this stuff you are studying is hard. Knowing that people study math for fun is scary.

    • @klasta2167
      @klasta2167 Рік тому

      @@ian.ambrose Im studying for fun too, im 16 lol 💀

  • @choo1030
    @choo1030 4 роки тому +8

    I honestly can't believe I've purchased a $150 textbook for contents that could be boiled down in 2 days worth of lecture videos. I'm not saying textbook is useless. But textbook has its limit as it cannot show the reader animations of how some things are done.
    Textbook is really only needed for practice problems.

  • @gp2580
    @gp2580 6 років тому +1

    Very interesting - always enjoy your videos - thank you

  • @zhoud2005
    @zhoud2005 4 роки тому

    Great lectures, really enjoyed them. thanks

  • @roronoazoro6153
    @roronoazoro6153 3 роки тому +6

    At the example at 4:38 the number 1/5 = 0.2 and 4/12 = 0.3 which is larger. The terms don't get smaller. How can this series converge?

    • @thesakinator7639
      @thesakinator7639 3 роки тому +1

      thats why its called conditionally convergent, because its convergency hinges on the fact that the terms ascilate from positive to negative so the sum does in fact get smaller and smaller

    • @DarinBrownSJDCMath
      @DarinBrownSJDCMath 2 роки тому +3

      Because any finite number of terms don't affect convergence, all that is required is that the terms are *eventually* decreasing, i.e. b_(n+1) = k for some k. This is something that happens a lot of the time, and it was glossed over in the video. You can check the terms are eventually decreasing by showing the derivative of x^2/(x^3 + 4) is eventually negative.

  • @NeymarJR-du9rb
    @NeymarJR-du9rb 6 років тому +1

    Thank you

  • @ian.ambrose
    @ian.ambrose 3 роки тому

    Thank you Professor.

  • @bapisaha1766
    @bapisaha1766 6 років тому +1

    Thank you professor

  • @محمودحقياسماعيلرشيد

    the minute 4:40 it is not 16/70 it is 16/68

  • @subforsubcommunitycenter6961
    @subforsubcommunitycenter6961 5 років тому +2

    Please add all the details about limits

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  5 років тому +3

      that's in another video earlier in the calculus playlist

    • @NewWesternFront
      @NewWesternFront Рік тому

      @@ProfessorDaveExplains sir please but what is 2+2 and how to prove it sir please sir

  • @newtoniangaming4832
    @newtoniangaming4832 3 роки тому +3

    10:51 but if we just apply
    limit n tends to infinity to (1+1/n)^n we get
    = (1 + 1/infinity)^infinity
    = (1+0)^infinity
    = 1
    so test must be inconclusive rather than divergent right?
    Please correct me if I am wrong.

    • @kjl3080
      @kjl3080 3 роки тому

      One word:
      E

    • @DarinBrownSJDCMath
      @DarinBrownSJDCMath 2 роки тому +1

      This is why it's terrible when teaching limits to students just learning, to do things like "plugging in infinity", as around the 5:00 mark. This kind of sloppy calculation is okay if you're experienced with limits and indeterminate forms, but it often leads students to wrong conclusions as you've done here. To answer your question, 1^(infinity) is an indeterminate form, and we cannot conclude any value for the limit. (1 + 1/n)^n does converge to e.

    • @kpkrkr4038
      @kpkrkr4038 Рік тому

      Same answer I get

  • @omerelhagahmed551
    @omerelhagahmed551 Місяць тому

    I think it's a typo at 2:25 it's "

  • @Nemoguzapomnit
    @Nemoguzapomnit 6 років тому +3

    Thx a lot fot that video! About problems at the end of the video: Σ[(-2)^n/3^n] is it relevant just to rewrite it as Σ[(-2/3)^n] and say that: as r=-2/3 and its less then 1, then the serires is converges?

    • @ravitheja012345
      @ravitheja012345 6 років тому +2

      r=-2/3 and |r|=2/3

    • @carultch
      @carultch 3 роки тому

      How do you pronounce the difference among "p", "п", and "π", when discussing mathematics in your language?

    • @Nemoguzapomnit
      @Nemoguzapomnit 3 роки тому

      @@carultch we don't use russian letters in math. But anyway "п" sounds like "pæ". And about "p" and "π" - in case with "p" we would say "p variable"

    • @carultch
      @carultch 3 роки тому

      @@Nemoguzapomnit Ok, that makes sense.
      Greek speakers dislike the fact that English speakers shift the vowel when referring to π, so that it sounds like pie. But we have to do that, otherwise both p and π would sound identical, like the word "pea". I found out that they say their own π to sound like like pea, and the Latin p like "pay", as it is most commonly named in languages that use Latin letters.
      I asked you, because I thought a similar issue might persist in your language, except with three different versions of the letter with very similar names.

    • @Nemoguzapomnit
      @Nemoguzapomnit 3 роки тому

      @@carultch it could be but we mostly never use "p" variables

  • @honeydevaang732
    @honeydevaang732 2 роки тому +1

    so as i understand, the alternative series and all the series associated with the calculus, we only need to find if they are convergent or divergent. but why do we have to do so? what is the relevance of convergence and divergence? maybe it could sound silly but this is my first interaction with the calculus so please pardon me for that.

    • @NewWesternFront
      @NewWesternFront Рік тому

      good question. I looked it up and the main answer i found was basically "to help you with even higher level math." whelp.

  • @ramiltaghiyev9712
    @ramiltaghiyev9712 2 роки тому

    7:53 guys, why is the series on the right divergent? I heard about the p-series

  • @yourfutureself4327
    @yourfutureself4327 Рік тому +1

    💚

  • @sciencedude2355
    @sciencedude2355 4 місяці тому

    how does the sum of (-1)^(n-1)/n converge if the sum of 1/n diverges?

  • @elanaweiss1120
    @elanaweiss1120 2 місяці тому

    why does it in the ratio test approach e

  • @kpkrkr4038
    @kpkrkr4038 Рік тому

    What is the use of series?

    • @xarlition
      @xarlition 10 місяців тому

      the simplest example is drug dosage calcs

  • @Dkdkxncnchz
    @Dkdkxncnchz 3 роки тому

    best