• UnderpantsWeevil@lemmy.world
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      5 months ago

      There’s a Real Analysis proof for it and everything.

      Basically boils down to

      • If 0.(9) != 1 then there must be some value between 0.(9) and 1.
      • We know such a number cannot exist, because for any given discrete value (say 0.999…9) there is a number (0.999…99) that is between that discrete value and 0.(9)
      • Therefore, no value exists between 0.(9) and 1.
      • So 0.(9) = 1
      • Kairos@lemmy.today
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        5 months ago

        Even simpler: 1 = 3 * 1/3

        1/3 =0.333333…

        1/3 + 1/3 + 1/3 = 0.99999999… = 1

        • UnderpantsWeevil@lemmy.world
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          5 months ago

          Even simpler

          0.99999999… = 1

          But you’re just restating the premise here. You haven’t proven the two are equal.

          1/3 =0.333333…

          This step

          1/3 + 1/3 + 1/3 = 0.99999999…

          And this step

          Aren’t well-defined. You’re relying on division short-hand rather than a real proof.