• AbidanYre@lemmy.world
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    28 days ago

    Is it also lazy to learn Roy G. Biv to know the color spectrum instead of learning all the physics and optical properties behind that?

    Or what about My Very Elderly Mother Just Served Us Nine Pickles to know the planets instead of learning orbital dynamics and astrophysics?

    Christ man, it’s a mnemonic device for elementary schoolers.

    • barsoap@lemm.ee
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      28 days ago

      Those two things are memorisation tasks. Maths is not about memorisation.

      You are not supposed to remember that the area of a triangle is a * h / 2, you’re supposed to understand why it’s the case. You’re supposed to be able to show that any triangle that can possibly exist is half the area of the rectangle it’s stuck in: Start with the trivial case (right-angled triangle), then move on to more complicated cases. If you’ve understood that once, there is no reason to remember anything because you can derive the formula at a moment’s notice.

      All maths can be understood and derived like that. The names of the colours, their ordering, the names of the planets and how they’re ordered, they’re arbitrary, they have no rhyme or reason, they need to be memorised if you want to recall them. Maths doesn’t, instead it dies when you apply memorisation.

      Ein Anfänger (der) Gitarre Hat Elan. There, that’s the Guitar strings in German. Why do I know that? Because my music theory knowledge sucks. I can’t apply it, music is all vibes to me but I still need a way to match the strings to what the tuner is displaying. You should never learn music theory from me, just as you shouldn’t learn maths from a teacher who can’t prove a * h / 2, or thinks it’s unimportant whether you can prove it.

      • Maths is not about memorisation

        It is for ROTE learners.

        You are not supposed to remember that the area of a triangle is a * h / 2

        Yes you are. A lot of students get the wrong answer when they forget the half.

        you’re supposed to understand why it’s the case

        Constructivist learners can do so, ROTE learners it doesn’t matter. As long as they all know how to do Maths it doesn’t matter if they understand it or not.

        You’re supposed to be able to show that any triangle that can possibly exist is half the area of the rectangle it’s stuck in

        No they’re not.

        If you’ve understood that once, there is no reason to remember anything because you can derive the formula at a moment’s notice.

        And if you haven’t understood it then there is a reason to remember it.

        you can derive the formula at a moment’s notice

        Students aren’t expected to be able to do that.

        All maths can be understood and derived like that

        It can be by Constructivist learners, not ROTE learners.

        The names of the colours, their ordering, the names of the planets and how they’re ordered, they’re arbitrary

        No they’re not. Colours are in spectrum order, the planets are in order from the sun.

        Maths doesn’t, instead it dies when you apply memorisation

        A very substantial chunk of the population does just fine with having memorised Maths.

          • AbidanYre@lemmy.world
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            23 hours ago

            But +, -, *, and / are all binary operators?

            As far as I know, the only reason multiplication and division come first is that we’ve all agreed to it. But it can’t be derived in a vacuum as that other dude contends it should be.

            • 💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱@programming.dev
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              16 hours ago

              But +, -, *, and / are all binary operators?

              No, only multiply and divide are. 2+3 is really +2+3, but we don’t write the first plus usually (on the other hand we do always write the minus if it starts with one).

              As far as I know, the only reason multiplication and division come first is that we’ve all agreed to it.

              No, they come first because you get wrong answers if you don’t do them first. e.g. 2+3x4=14, not 20. All the rules of Maths exist to make sure you get correct answers. Multiplication is defined as repeated addition - 3x4=3+3+3+3 - hence wrong answers if you do the addition first (just changed the multiplicand, and hence the answer). Ditto for exponents, which are defined as repeated multiplication, a^2=(axa). Order of operations is the process of reducing everything down to adds and subtracts on a number line. 3^2=3x3=3+3+3

        • barsoap@lemm.ee
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          28 days ago

          Nothing. And that’s why people don’t write equations like that: You either see

               4
          6 + ---
               2
          

          or

           6 + 4
          -------
             2
          

          If you wrote 6 + 4 / 2 in a paper you’d get reviewers complaining that it’s ambiguous, if you want it to be on one line write (6+4) / 2 or 6 + (4/2) or 6 + ⁴⁄₂ or even ½(6 + 4) Working mathematicians never came up with PEMDAS, which disambiguates it without parenthesis, US teachers did. Noone else does it that way because it does not, in the slightest, aid readability.

          • And that’s why people don’t write equations like that

            Says someone who clearly hasn’t looked in any Maths textbooks

            If you wrote 6 + 4 / 2 in a paper you’d get reviewers complaining that it’s ambiguous

            Only if their Maths was very poor. #MathsIsNeverAmbiguous

            Working mathematicians never came up with PEMDAS

            Yes they did.

            which disambiguates it without parenthesis

            It was never ambiguous to begin with.

            Noone else does it that way

            Says someone who has never looked in a non-U.S. Maths textbooks - BIDMAS, BODMAS, BEDMAS, all textbooks have one variation or another.