Rearrange a series

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  • เผยแพร่เมื่อ 5 ก.พ. 2025
  • In this video, I define what it means to rearrange (or reshuffle) a series and show that if a series converges absolutely, then any rearrangement of the series converges to the same limit.
    Interesting Consequence: • Riemann Series Theorem
    Series Playlist: • Series
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ความคิดเห็น • 26

  • @jkid1134
    @jkid1134 4 ปีที่แล้ว +6

    Can't believe this gem is hidden

  • @noahtaul
    @noahtaul 3 ปีที่แล้ว +10

    I predict this is the next video you will make public, maybe sometime in the next week!

    • @drpeyam
      @drpeyam  3 ปีที่แล้ว +4

      You were right!!!

  • @kevin326520
    @kevin326520 3 ปีที่แล้ว

    Wonderful video! I was told in class about this fact and to be aware about the conditional convergent series about the re-ordering since in that case, it actually make a difference. However, I have never seen a proof of this. This is actually really interesting and harder than I thought! Thanks!

  • @cbbuntz
    @cbbuntz 3 ปีที่แล้ว +1

    My first thought is this is just a passive aggressive way to say blackpenredpen is wrong about the "1/3 of positive integers are even" or whatever

  • @dgrandlapinblanc
    @dgrandlapinblanc 2 ปีที่แล้ว

    Cool. Thank you very much.

  • @Kdd160
    @Kdd160 3 ปีที่แล้ว +2

    nice explain!

  • @orenfivel6247
    @orenfivel6247 ปีที่แล้ว

    Is there a video that proofs: if (and maybe only if also) f:ℕ→ℕ is a bijection (i.e., f(n) is the rearrangement or the permutation of the natural #'s), then f(n)→∞ as n→∞?
    Is it true also we need to demand that for all finite n∈ ℕ, f(n) must be finite?

    • @drpeyam
      @drpeyam  ปีที่แล้ว +1

      You can do it by contradiction, by arguing that in this case f must be bounded

    • @orenfivel6247
      @orenfivel6247 ปีที่แล้ว

      @@drpeyam i did it but i wanted to see that kind of video of you

  • @andrewren1663
    @andrewren1663 10 หลายเดือนก่อน

    At 2:50 I think the series of rearrangement \sum (x_n)'= the original series \sum x_n
    eq \sum |x_n|?

  • @lasithanirmitha321
    @lasithanirmitha321 3 ปีที่แล้ว +1

    Hey Dr Payem, don't we need to take m to be max(N, kp+1,...,kN).

    • @drpeyam
      @drpeyam  3 ปีที่แล้ว +1

      It’s implicit

  • @harikishan5690
    @harikishan5690 3 ปีที่แล้ว +1

    cool!!

  • @abduhalloqovabdusamad3849
    @abduhalloqovabdusamad3849 3 ปีที่แล้ว

    отличное решение

  • @123pok456ey
    @123pok456ey 3 ปีที่แล้ว

    The order of this video and the video "Riemann Series Theorem" are rearranged

  • @yoav613
    @yoav613 3 ปีที่แล้ว +1

    Dr peyam you are taking abig risk here, cause now if you ask your students in the test find the infinite sum.. they can go after the test and tell you my answer is correct i just rearranged it!

  • @pierreabbat6157
    @pierreabbat6157 3 ปีที่แล้ว +2

    The tail of the Ceres? But Ceres isn't a comet!

    • @drpeyam
      @drpeyam  3 ปีที่แล้ว +1

      Hahaha

  • @Mathcambo
    @Mathcambo 3 ปีที่แล้ว

    Can you teach topology

    • @drpeyam
      @drpeyam  3 ปีที่แล้ว +2

      See topology playlist

  • @Mathcambo
    @Mathcambo 3 ปีที่แล้ว

    Can you teach matric space

  • @Idtelos
    @Idtelos 3 ปีที่แล้ว

    the answer is -1/12...that's my answer to real numbers... I would prove it, but I'll leave that reader. :p

    • @drpeyam
      @drpeyam  3 ปีที่แล้ว

      Hahaha