• @Andonno
    link
    08 months ago

    Not really.

    1/3 = 0.3•

    1/3 + 1/3 + 1/3 = 0.3• + 0.3• + 0.3•

    3/3 = 0.9•

    1 = 0.9•

    And that’s only one proof, there are others.

    • @[email protected]
      link
      fedilink
      88 months ago

      This is not a proof as you start with the answer, albeit disguised as a known truth. Here is a real proof. Start by assigning the recurring decimal a variable.

      x = 0.9999...
      

      Now calculate 10 times this by shifting the decimal place.

      10x = 9.9999...
      

      You can then subtract the second equation from the first. Note that all the digits after the decimal cancel out, leaving us with the following.

      9x = 9
      x = 1
      

      Therefore, 0.9999… = 1. Infinity does weird things!

    • @[email protected]
      link
      fedilink
      28 months ago

      can 0.3• + 0.3• + 0.3• be really be added to equal 0.9• the same way that 0.3 + 0.3 + 0.3 = 0.9 though? and if so, is it proven or assumed? im not saying ur wrong btw, just asking. and does 0.000…001 equal 0?

      • Karyoplasma
        link
        fedilink
        2
        edit-2
        8 months ago

        0.3• has infinte decimals, 0.0000…001 does not. No matter how many zeroes you put before the one, there will never be infinite zeroes, so it’s not equal to 0.

        You simply cannot have “Infinity + 1” decimals, since infinity + 1 = infinity.

      • @[email protected]
        link
        fedilink
        18 months ago

        There is actually a smallest number, typically denoted by a lower case epsilon, which is infintesimally small, typically used in calculus proofs.

    • Tedesche
      cake
      link
      English
      18 months ago

      I’m not a math person at all, so I’m not really debating your proof, but it seems to me that if 0.9• = 1, then what does 0.1• equal? It “fits” perfectly into the “space” between 0.9• and 1, but if 0.9•=1 then 0.1• should equal 0, right? Except it doesn’t, because 0.1<0.1• and 0.1 definitely isn’t 0.

      I definitely understand why some religious people think numbers are a tool of Satan.

      • @[email protected]
        link
        fedilink
        English
        28 months ago

        It’s infinite ones - as you expand it, the illusion offered by the single digit disappears. 0.999 + 0.111 is 1.11, so 0.999… + 0.111… is 1.111…

        • Tedesche
          cake
          link
          English
          18 months ago

          My calculator agrees with you but it still doesn’t make intuitive sense to my brain. 0.1• still seems like it “fits” neatly into 0.9• to create 1.

          Ah, well. Good thing I’m not designing bridges, right?

          • Blyfh
            link
            28 months ago

            Think of it with fewer digits.
            If we have 0.999 and 0.111, then yeah, each 1 neatly complements each 9. But you have to consider that each of them result in a 1 the next digit upwards (as 09 + 01 = 10). So 0.999 + 0.111 equals 1.110. What you actually want here is 0.001, which just complements the last 9, which returns a 1 for the next 9, which returns a 1 for the next 9 and so on. 0.999 + 0.001 = 1.000. If you increase the digits, the zeros between the decimal point and the one increase too, causing the number to get smaller and smaller. If continue this infinitely long, the number becomes 0.

            0.999• + 0.000• = 1.000•