0.8888… = 1 (in base 9)

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  • Опубліковано 31 січ 2025

КОМЕНТАРІ • 68

  • @UserYouTube506
    @UserYouTube506 5 місяців тому +82

    Math in school: 🥱
    Math in internet: 🤩

  • @anujthakur3016
    @anujthakur3016 3 місяці тому +4

    This is basically geometric progression in which the common multiple r has value less than 1 so show the formula to get sum of infinity a/(1-r) can be used ,its the same thing. Btw a is the first term in the above formula

  • @aireyroblox
    @aireyroblox 5 місяців тому +25

    So basically for any n, 0.nnn repeating will be equal to 1 in base n+1

    • @dougr.2398
      @dougr.2398 5 місяців тому +3

      For n = integer and less than or equal to 9.

    • @raph-ko1706
      @raph-ko1706 5 місяців тому +3

      @@dougr.2398Why would the pattern stop for n>9 ?

    • @dougr.2398
      @dougr.2398 5 місяців тому +2

      @@raph-ko1706 because the decimal representation is base 10

    • @dougr.2398
      @dougr.2398 5 місяців тому +2

      Base 10 only uses digits 0 through 9 in its decimal representation

    • @raph-ko1706
      @raph-ko1706 5 місяців тому +2

      @@dougr.2398 Fair answer thanks 🙂

  • @pieceofwaterofficial330
    @pieceofwaterofficial330 3 місяці тому +1

    1. Let 0.(n)=x
    2. Multiply both sides by 10
    n.(n)=10x
    3. Substract x from both sides
    n.(n)-0.(n)=10x-x
    n=9x
    x=n/9
    4. Recall 0.(n)=x
    0.(n)=n/9

  • @horriblememes
    @horriblememes 5 місяців тому +38

    I mean yeah you can do this with any fraction

    • @raysye4775
      @raysye4775 5 місяців тому +1

      He does

    • @budderman3rd
      @budderman3rd 5 місяців тому +1

      Nooooooo. Really?

    • @otinaj
      @otinaj 5 місяців тому +1

      Only with fractions >= 1/2

    • @raysye4775
      @raysye4775 5 місяців тому

      @@otinajNo, any works, 3/4, 9/10, 1/7, anything

    • @jamesmarlowebito8982
      @jamesmarlowebito8982 5 місяців тому

      ​​@@raysye4775 It works for >

  • @husnuozel9031
    @husnuozel9031 5 місяців тому +3

    Beautiful ❤️

  • @FaerieDragonZook
    @FaerieDragonZook 5 місяців тому

    The areas may be equal in measure, but there is a point in the center of the square that is never shaded. One way you can think of this is that the limiting difference between 0.888..._9 and 1.0 is an infinitesimal.

    • @dougr.2398
      @dougr.2398 5 місяців тому

      Infinite space is only reached in infinite time

  • @Azuro123-pj7xj
    @Azuro123-pj7xj 5 місяців тому +14

    Isn't x-1 over x + x-1 over x² + x-1 over x³ ... always 1?

  • @J3ff_K1ng
    @J3ff_K1ng 5 місяців тому +1

    I've just realised that this videos of proving that something is 1 in base X is not as impressive since it's just like 0.999... is 1 in base 10 lol

  •  5 місяців тому +10

    0.nnnnnn is 1 in base n+1

    • @JoaoGabriel-ew4ic
      @JoaoGabriel-ew4ic 5 місяців тому +1

      Prove it

    • @jamesmarlowebito8982
      @jamesmarlowebito8982 5 місяців тому +1

      7/8 + 7/8² + 7/8³ + 7/8⁴ + ... + 7/8^n = 1
      That means
      (0.7777777...) in base 8 is 1

    • @goosemchonk
      @goosemchonk 5 місяців тому

      ​​@@JoaoGabriel-ew4ic
      In base b such that b != 1 and b is a natural number and for n such that n = b-1;
      0.nnn.... = n/10 + n/100 + n/1000 +...
      0.nnn... = n/10 + n/(10^2) + n/(10^3) +...
      0.nnn... = n(1/10 + 1/(10^2) + 1/(10^3) +...)
      0.nnn... = n * sum 1/(10^k) k->infinity
      1/(10^k) = (1/10)^k
      0.nnn... = n * sum (1/10)^k k->infinity
      sum r^k k-> infinity = r/(1-r)
      0.nnn... = n * (1/10)/(1-(1/10))
      1 - 1/10 in base b = (b-1)/10
      0.nnn... = n * (1/10)/(n/10)
      0.nnn... = n * (1/10) * (10/n)
      0.nnn... = n * 10/10n
      0.nnn... = n * 1/n
      0.nnn... = n/n = 1 QED

    • @FelanLP
      @FelanLP 5 місяців тому

      How proof shoe r.​@@JoaoGabriel-ew4ic

    • @FelanLP
      @FelanLP 5 місяців тому

      ​@@JoaoGabriel-ew4ic for proof show the video xD

  • @mitsunam7001
    @mitsunam7001 5 місяців тому +2

    How many series are left with these proofs?

    • @MathVisualProofs
      @MathVisualProofs  5 місяців тому +1

      Wanted one for each base from 2 to 10. Just need base 6 at this point.

  • @brianhale2977
    @brianhale2977 5 місяців тому

    Or we can be perfectly happy knowing that the area of the square is one square and go about the rest of our days without obsessing over tic tac toe boards. 😅

  • @purple_m0rse
    @purple_m0rse 5 місяців тому +3

    0.99...=1 in base 10

  • @scottabroughton
    @scottabroughton 5 місяців тому +8

    You could also do 0.eee = 1 in hexadecimal.

    • @MathVisualProofs
      @MathVisualProofs  5 місяців тому +7

      I was trying to get one for each base from 2 to 10. But maybe I’ll work on that one too :)

    • @scottabroughton
      @scottabroughton 5 місяців тому

      @@MathVisualProofs Since 16 is square, a 4x4 would make a nice visual.

    • @narfharder
      @narfharder 5 місяців тому +4

      That's pentadecimal, 0.FFF... = 1 in base 16.

    • @scottabroughton
      @scottabroughton 5 місяців тому

      @@narfharder F is 16 in hexadecimal. The repeating decimal is one less than the base, so 0.eee is for hexadecimal.

    • @LelioS
      @LelioS 5 місяців тому +3

      ​@@scottabroughtonNo, F in hex is 15 in dec

  • @FelanLP
    @FelanLP 5 місяців тому

    Good example how 0.99999... is equal to 1 (in base 10).

  • @FPSDECEM
    @FPSDECEM 5 місяців тому +1

    8/9=0,(8)≠1

  • @BennoRob95
    @BennoRob95 5 місяців тому

    Asymptoticism should be a word because this would be Antiasymtoticism

  • @jasonhilliker492
    @jasonhilliker492 5 місяців тому +1

    Wouldn't it be more accurate to say it approaches 1 instead of equals 1?

    • @MathVisualProofs
      @MathVisualProofs  5 місяців тому +6

      The sequence of finite sums approaches 1 for sure. But the infinite sum IS the limit of the sequence of finite sums so the infinite sum is 1.

    • @budderman3rd
      @budderman3rd 5 місяців тому

      Wrong

    • @jamesmarlowebito8982
      @jamesmarlowebito8982 5 місяців тому

      ​@@budderman3rd You are 0 years old but you know nothing.

    • @raph-ko1706
      @raph-ko1706 4 місяці тому +1

      @@jasonhilliker492 We put the equal sign when we speak about limits, but sure it means by approaching

    • @Chris-5318
      @Chris-5318 Місяць тому

      To be clear, the series 8/9 + 8/9^2 + 8/9^3 + 8/9^4 + ... has the sequence of partial sums: 8/9, 8/9 + 8/9^2, 8/9 + 8/9^2 + 8/9^3, .... The sum of the series is the limit of the seqeunce of the partial sums, and that is (using the geometric series formula) (8/9) / ( 1 - 1/9) = 1.
      If you prefer [the sum of] 0.888... (base 9) = lim n->oo 0.888...8 (base 9) (n 8s) = lim n->oo 1 - 1/9^n = 1

  • @codatheseus5060
    @codatheseus5060 5 місяців тому +3

    0.0000000... = 1 in base 1

    • @Naej7
      @Naej7 5 місяців тому +1

      No

    •  5 місяців тому +1

      ​@@Naej7Yes and no. Only 0 exist in base 1. But base 1 has no fixed numerical values.

    • @Jar.in.a.Bottle
      @Jar.in.a.Bottle 5 місяців тому +1

      Well, there is at least the very singular imaginary number system in base 1, unless somehow there isn't.

    • @jamesmarlowebito8982
      @jamesmarlowebito8982 5 місяців тому +1

      Then it's 25% true and 75% false that 0 = 1 in base 1.
      But
      If one of those hits 0, that means it's true or false.
      But
      There's a probability that one of those gets to 0%.

    • @Jar.in.a.Bottle
      @Jar.in.a.Bottle 5 місяців тому

      @Naej7 i0, and maybe j0...? I see that surely i0=0 at first glance, but does it at somekind of infinity or the like? After all, set theory is entirely base upon the empty set as the starting notion, then counting the number of empty sets under consideration to reach higher numbers and sets of numbers and things. Right?

  • @imaginaryunitlord
    @imaginaryunitlord Місяць тому +1

    well 0.99999999...=1 base 10

  • @MobarakHossen-v7o
    @MobarakHossen-v7o 3 місяці тому +1

    (0.88888...)9=1