• hydroptic@sopuli.xyz
    link
    fedilink
    English
    arrow-up
    79
    arrow-down
    1
    ·
    edit-2
    8 months ago

    And mathematicians divide by multiplying!

    In formal definitions of arithmetics, division can be defined via multiplication: as a simplified example with real numbers, because a ÷ 2 is the same as a × 0.5, this means that if your axioms support multiplication you’ll get division out of them for free (and this’ll work for integers too, the definition is just a bit more involved.)

    Mathematicians also subtract by adding, with the same logic as with division.

    • bort@feddit.de
      link
      fedilink
      English
      arrow-up
      14
      ·
      8 months ago

      if your axioms support multiplication you’ll get division out of them for free

      this is true… except when it isn’t.

      In mathematics, rings are algebraic structures that generalize fields: multiplication need not be commutative and multiplicative inverses need not exist

      https://en.wikipedia.org/wiki/Ring_(mathematics)

      • hydroptic@sopuli.xyz
        link
        fedilink
        English
        arrow-up
        13
        arrow-down
        1
        ·
        edit-2
        8 months ago

        Yeah I should maybe just have written

        if your axioms support multiplication you’ll get division out of them for free*

        *certain terms and conditions may apply. Limited availability in some structures, North Korea, and Iran. Known to the state of California to cause cancer or reproductive toxicity

    • meowMix2525
      link
      fedilink
      English
      arrow-up
      12
      ·
      edit-2
      8 months ago

      Right. The cells are dividing in half, which would be represented in math form by 1/0.5 = 2. Dividing by one half is the same thing as multiplying by 2, and division in general is really just a visually simplified way to multiply by a fraction of 1.

      Any time you divide by some fraction of 1, you will necessarily end up with a larger number because you’re doubling that division which reverses it back into multiplication, much in the same way as a negative x negative = positive. If that makes sense.

      A mathematician would not be bothered by this. A high schooler taking algebra I might be though, if you phrased it the same way this post did.

    • Kogasa@programming.dev
      link
      fedilink
      English
      arrow-up
      8
      arrow-down
      1
      ·
      8 months ago

      a/b is the unique solution x to a = bx, if a solution exists. This definition is used for integers, rationals, real and complex numbers.

      Defining a/b as a * (1/b) makes sense if you’re learning arithmetic, but logically it’s more contrived as you then need to define 1/b as the unique solution x to bx = 1, if one exists, which is essentially the first definition.

      • Artyom
        link
        fedilink
        English
        arrow-up
        4
        ·
        8 months ago

        That’s me, a degree-holding full time computer scientist, just learning arithmetic I guess.

        Bonus question: what even is subtraction? I’m 99% sure it doesn’t exist since I’ve never used it, I only ever use addition.

          • Artyom
            link
            fedilink
            English
            arrow-up
            1
            ·
            8 months ago

            Now you just replaced one incalculable thing with a different incalculable thing.

              • Artyom
                link
                fedilink
                English
                arrow-up
                2
                ·
                8 months ago

                Computers don’t subtract, and you can’t just add a negative, a computer can’t interpret a negative number, it can only store a flag that the number is negative. You need to use a couple addition tricks to subtract to numbers to ensure that the computer only has to add. It’s addition all the way down.

        • hydroptic@sopuli.xyz
          link
          fedilink
          English
          arrow-up
          2
          arrow-down
          1
          ·
          edit-2
          8 months ago

          what even is subtraction?

          It’s just addition wearing a trench coat, fake beard and glasses

      • hydroptic@sopuli.xyz
        link
        fedilink
        English
        arrow-up
        1
        arrow-down
        1
        ·
        edit-2
        8 months ago

        Defining a/b as a * (1/b) makes sense if you’re learning arithmetic

        The example was just to illustrate the idea not to define division exactly like that

  • Omega_Haxors@lemmy.ml
    link
    fedilink
    English
    arrow-up
    16
    ·
    edit-2
    8 months ago

    Computers multiply by adding, subtract by adding, i’m not sure how division goes but i’m sure that’s addition too.

        • icydefiance
          link
          fedilink
          English
          arrow-up
          4
          ·
          edit-2
          8 months ago

          The other replies are simplifying too much. Just adding or subtracting in a loop would be far too slow.

          A multiplier will find the partial products by using AND gates, and then sum them, which is very similar to long multiplication as they teach you in school. This article explains it pretty well.

          Division is more complicated. It’s sort of done like long division, but apparently that is slow and there’s some magic with two’s complements that can make it faster. Honestly I don’t fully understand it yet.

          • SturgiesYrFase@lemmy.ml
            link
            fedilink
            English
            arrow-up
            2
            ·
            8 months ago

            That article was really good. I feel like if someone explained it to me at a pub or party I could somewhat talk about it without sounding like a total ludite.

        • Xavienth@lemmygrad.ml
          link
          fedilink
          English
          arrow-up
          2
          ·
          8 months ago

          Subtract divisor from dividend until you hit zero. Number of subtractions is the quotient. Don’t ask about non-whole numbers.

        • Omega_Haxors@lemmy.ml
          link
          fedilink
          English
          arrow-up
          2
          ·
          edit-2
          8 months ago

          It recursively subtracts until the number goes at or below zero. The iterations is the output and the reminder is how much it went below zero.

  • Cap@kbin.social
    link
    fedilink
    arrow-up
    10
    ·
    8 months ago

    Clever and I get the joke and it made me smile. If I recall my biology from 20 years ago I think the cell makes duplicates of its chromosomes then splits apart. So you have two cells inside one membrane that separates, 2 / 1 = 2. The way I first thought about it was one cell splitting in half, so half goes to one cell, the other half with the other, 1 / .5 = 2.

    In short, I think the math works out fine, but the language you use to describe it can lead to comedy gold. You could say cells reproduce by division? I don’t know, I’m not a biologist or mathematician. I’m a toilet poster.

  • faintwhenfree@lemmus.org
    link
    fedilink
    English
    arrow-up
    8
    ·
    8 months ago

    No comments about Amitabh Bachchan’s use for meme. Well it should have been a long time coming, I’m glad that it’s now here.

    • Rascabin@lemmy.ml
      link
      fedilink
      English
      arrow-up
      3
      ·
      8 months ago

      Bollywood itself is a meme 🤭. Just watch their version of The Matrix. Dude starts singing with “Trinity”, like wtf!??

  • OpenStars@startrek.website
    link
    fedilink
    English
    arrow-up
    5
    ·
    8 months ago

    That’s the problem whenever math meets physics: the former wins in the theory, but in the real world physics always triumphs:-).