Proof: The Rationals are Dense in the Reals | Real Analysis

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  • Опубліковано 10 лис 2024

КОМЕНТАРІ • 26

  • @xpp1e
    @xpp1e 3 місяці тому +8

    The proof is a bit misleading as it uses an additional property of the integers that is not mentioned here. Namely that for any real number x there exists a minimal integer k such that k - 1

  • @jinglepinglepie611
    @jinglepinglepie611 9 місяців тому +3

    oh my goodness, you filmed this at 2 am? Thanks for your hard work XD

    • @WrathofMath
      @WrathofMath  9 місяців тому +1

      Always on the grind! Thanks for watching!

  • @wtt274
    @wtt274 Рік тому +4

    This is an abstract and difficult concept . However , it has been so clearly explained in this great video .Thank you for your great work ❤

  • @lox7182
    @lox7182 4 місяці тому +1

    if anyone's curious about the irrationals
    if a and b are irrational, atleast one of (a+b)/2 or (a+3b)/4 will be irrational, if both were rational, then (a+3b)/2 would be rational and (a+3b)/2 - (a+b)/2 = 2b/2 = b would be rational, which wouldn't make sense
    if only one of them is irrational, just do (a+b)/2
    if both are rational, do (a + pi(b))/(1+pi), since that is just equal to b - (b-a)/(1+pi) and b-a isn't zero, it's irrational

  • @mandeath2971
    @mandeath2971 10 місяців тому

    Hey, I love you. Continue the good work.

    • @WrathofMath
      @WrathofMath  10 місяців тому +1

      Hey, thanks! I will, until I turn to dust

  • @sugathmudalige1265
    @sugathmudalige1265 Рік тому

    Great video. Is any course available for " Foundaton of Mathematics"

  • @Jancel705
    @Jancel705 3 місяці тому

    can we chose m=a-b and n=2 and work from there?

  • @Aman_iitbh
    @Aman_iitbh Рік тому +1

    ooh finaaly its in playlist

    • @WrathofMath
      @WrathofMath  Рік тому +1

      Yes indeed - and you're early, the lesson isn't even out yet! Hope you find the playlist helpful!

    • @Aman_iitbh
      @Aman_iitbh Рік тому +1

      @@WrathofMath yes its life saving playlist .
      btw how can we show any number is between two consecutive natural number as u used that m-1

    • @WrathofMath
      @WrathofMath  Рік тому +1

      We can consider the set of all positive integers greater than na. Then the well ordering principle guarantees a smallest member of this set: m, and then m-1 must be

    • @Aman_iitbh
      @Aman_iitbh Рік тому

      @@WrathofMath yes ,but this will proof for all positive integer i think , if na is negative like -4.12 then we need to proof its between -4 to -5 .does well ordering can proof this?

    • @Aman_iitbh
      @Aman_iitbh Рік тому +1

      @@WrathofMath and will u make vedio on well ordering too later ? plz

  • @Rahma_mamoun
    @Rahma_mamoun Рік тому

    Keep going 🎉🎉🎉🎉thx a lot ❤❤❤

  • @AblieFatty-pb3ds
    @AblieFatty-pb3ds Рік тому

    it's a great video thumbs up. if i may ask, y do u have replace "a" by "b-1/n"

    • @MelquisedecLozano
      @MelquisedecLozano Місяць тому

      Same question here. I figured that showing that m is less than or equal to a + 1/n is enough to show that m/n is less than b. Did you every find an answer?

  • @priyankaparikh8265
    @priyankaparikh8265 7 місяців тому

    Is there a video on dedekind cuts and their use in forming the reals?

    • @WrathofMath
      @WrathofMath  7 місяців тому

      I haven't made one yet, but it would be a lot of fun to create such a video - maybe later this year when I have some more time. Would like to come back to producing for the Real Analysis playlist but right now it's hard to afford working on just because it's so niche. Lots more topics will be covered eventually though!

  • @punditgi
    @punditgi Рік тому +6

    One would have to be dense not to be a fan of Wrath of Math! 😂

  • @sumitlama4109
    @sumitlama4109 Рік тому +1

    if x is a real number, prove that -x≤|x| can you prove this

    • @VS-is9yb
      @VS-is9yb Рік тому +1

      One can just consider separate cases: x is positive,
      x is zero,
      x is negative
      In all these cases the inequality is trivial, and there is no other case.