• Kalkaline @lemmy.one
    link
    fedilink
    arrow-up
    34
    arrow-down
    3
    ·
    1 year ago

    It’s so dumb and it makes perfect sense at the same time. There is an infinitely small difference between the two numbers so it’s the same number.

    • KoboldCoterie@pawb.social
      link
      fedilink
      arrow-up
      53
      arrow-down
      1
      ·
      edit-2
      1 year ago

      There is no difference, not even an infinitesimally small one. 1 and 0.999… represent the exact same number.

        • funnystuff97@lemmy.world
          link
          fedilink
          arrow-up
          5
          ·
          edit-2
          1 year ago

          Right, it’s only a problem because we chose base ten (a rather inconvenient number). If we did math in base twelve, 1/3 in base twelve would simply be 0.4. It doesn’t repeat. Simply, then, 1/3 = 0.4, then (0.4 × 3) = (0.4 + 0.4 + 0.4) = 1 in base twelve. No issues, no limits, just clean simple addition. No more simple than how 0.5 + 0.5 = 1 in base ten.

          One problem in base twelve is that 1/5 does repeat, being about 0.2497… repeating. But eh, who needs 5? So what, we have 5 fingers, big whoop, it’s not that great of a number. 6 on the other hand, what an amazing number. I wish we had 6 fingers, that’d be great, and we would have evolved to use base twelve, a much better base!

          • clutchmatic@lemmy.world
            link
            fedilink
            arrow-up
            1
            ·
            1 year ago

            I mean, there is no perfect base. But the 1/3=0.333… thing is to be understood as a representation of that 1 split three ways

        • KoboldCoterie@pawb.social
          link
          fedilink
          arrow-up
          15
          arrow-down
          1
          ·
          1 year ago

          An infinitesimal is a non-zero number that is closer to zero than any real number. An infinitesimal is what would have to be between 0.999… and 1.

            • KoboldCoterie@pawb.social
              link
              fedilink
              arrow-up
              8
              ·
              edit-2
              1 year ago

              It’s a weird concept and it’s possible that I’m using it incorrectly, too - but the context at least is correct. :)

              Edit: I think I am using it incorrectly, actually, as in reality the difference is infinitesimally small. But the general idea I was trying to get across is that there is no real number between 0.999… and 1. :)

              • LegendofZelda64@lemmy.fmhy.ml
                link
                fedilink
                arrow-up
                2
                arrow-down
                1
                ·
                1 year ago

                I think you did use it right tho. It is a infinitesimal difference between 0.999 and 1.

                “Infinitesimal” means immeasurably or incalculably small, or taking on values arbitrarily close to but greater than zero.

                • Kogasa@programming.dev
                  link
                  fedilink
                  arrow-up
                  4
                  ·
                  1 year ago

                  The difference between 0.999… and 1 is 0.

                  It is possible to define a number system in which there are numbers infinitesimally less than 1, i.e. they are greater than every real number less than 1 (but are not equal to 1). But this has nothing to do with the standard definition of the expression “0.999…,” which is defined as the limit of the sequence (0, 0.9, 0.99, 0.999, …) and hence exactly equal to 1.

          • Ghoelian@feddit.nl
            link
            fedilink
            arrow-up
            2
            ·
            1 year ago

            Wait what

            I always thought infinitesimal was one of those fake words, like gazillion or something

            • KoboldCoterie@pawb.social
              link
              fedilink
              arrow-up
              3
              ·
              1 year ago

              It sounds like it should be, but it’s actually a real (or, non-real, I suppose, in mathematical terms) thing! :)

    • iAmTheTot@kbin.social
      link
      fedilink
      arrow-up
      28
      arrow-down
      2
      ·
      1 year ago

      No, it’s not “so close so as to basically be the same number”. It is the same number.

      • nachom97@lemmy.world
        link
        fedilink
        arrow-up
        5
        ·
        1 year ago

        They said its the same number though, not basically the same. The idea that as you keep adding 9s to 0.9 you reduce the difference, an infinite amount of 9s yields an infinitely small difference (i.e. no difference) seems sound to me. I think they’re spot on.

        • iAmTheTot@kbin.social
          link
          fedilink
          arrow-up
          8
          arrow-down
          2
          ·
          1 year ago

          No, there is no difference. Infitesimal or otherwise. They are the same number, able to be shown mathematically in a number of ways.

          • nachom97@lemmy.world
            link
            fedilink
            arrow-up
            7
            arrow-down
            1
            ·
            1 year ago

            Yes, thats what we’re saying. No one said it’s an infinitesimally small difference as in hyperbolically its there but really small. Like literally, if you start with 0.9 = 1-0.1, 0.99 = 1-0.01, 0.9… n nines …9 = 1-0.1^n. You’ll start to approach one, and the difference with one would be 0.1^n correct? So if you make that difference infinitely small (infinite: to an infinite extent or amount): lim n -> inf of 0.1^n = 0. And therefore 0.999… = lim n -> inf of 1-0.1^n = 1-0 = 1.

            I think it’s a good way to rationalize, why 0.999… is THE SAME as 1. The more 9s you add, the smaller the difference, at infinite nines, you’ll have an infinitely small difference which is the same as no difference at all. It’s the literal proof, idk how to make it more clear. I think you’re confusing infinitely and infinitesimally which are not at all the same.

          • mrcarrot@lemmy.calebmharper.com
            link
            fedilink
            arrow-up
            2
            ·
            1 year ago

            Technically you’re both right as there are no infinitesimals in the real number system, which is also one of the easiest ways to explain why this is true.

      • Dandroid@dandroid.app
        link
        fedilink
        arrow-up
        0
        arrow-down
        2
        ·
        1 year ago

        That’s what it means, though. For the function y=x, the limit as x approaches 1, y = 1. This is exactly what the comment of 0.99999… = 1 means. The difference is infinitely small. Infinitely small is zero. The difference is zero.