• moriquende@lemmy.world
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    21 days ago

    Wouldn’t we just assume function expressions are always “in parenthesis”? Then it’s just a substitution and no rules were changed.

      • moriquende@lemmy.world
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        4 days ago

        But factorised terms are multiplications, so they’re still following the same rules: a(b+c) = a*(b+c)

        Example: 2(3+5)=16, and also 2*3+2*5=16

        • 💡𝚂𝗆𝖺𝗋𝗍𝗆𝖺𝗇 𝙰𝗉𝗉𝗌📱@programming.dev
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          4 days ago

          But factorised terms are multiplications,

          No, they’re Distribution done in the Brackets step, a(b+c)=(ab+ac), now solve (ab+ac)

          a(b+c) = a*(b+c)

          Nope! a(b+c)=(ab+ac). 1/a(b+c)=1/(ab+ac), but 1/ax(b+c)=(b+c)/a.

          23+25=16

          (2x3+2x5) actually, or you’ll get the wrong answer when it follows a Division sign. See previous point

              • moriquende@lemmy.world
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                3 days ago

                Yes, the math textbook says exactly what I said, that it’s a multiplication. There’s no mention of it being a separate operation taking precedence. The parentheses in your example are added for clarity.

                Whether you give priority to juxtapositions is an open debate with the consensus being to just use parenthesis around when writing in a single line to avoid confusion. However, there is no distribution step taking precedence, as you mentioned, and the whole debate centers around whether the writer was too lazy to add parenthesis.

                • Yes, the math textbook says exactly what I said, that it’s a multiplication

                  Nope, they say it’s Brackets

                  5(36)=(5x36) <== Brackets

                  bc=(3x4) <== Brackets

                  There’s no mention of it being a separate operation taking precedence

                  It’s part of the Brackets step. I have no idea what “separate operation” you’re talking about

                  The parentheses in your example are added for clarity

                  Nope. They are there because The Distributive Law requires them. “those who study algebra are required to make their calculations conform to these laws”.

                  Whether you give priority to juxtapositions is a

                  A literal Law of Maths. See textbook.

                  the consensus being to just use parenthesis around when writing in a single line to avoid confusion.

                  No it isn’t. You won’t find any Maths textbook that says that.

                  However, there is no distribution step taking precedence

                  There is the Brackets step, including Distribution, taking precedence, as per Maths textbooks 🙄

                  as you mentioned

                  As the textbooks mention

                  the whole debate centers around whether the writer was too lazy to add parenthesis

                  The only debate is by people like you ignoring what is taught in Maths textbooks.

                  • moriquende@lemmy.world
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                    3 days ago

                    Nowhere in your “proof” screenshots does it say anything about distribution being part of the brackets step. Distribution is a method that can help solve equations, but it isn’t required. If you have 2(3+5) you’re free to solve it as 2*3+2*5 or as 2*8, whichever is easiest. That is because juxtaposition means multiplication and nothing else.

                    Math textbooks almost universally will either use clear brackets or simply write divisions in 2 lines, which avoids the confusion altogether.