Does anybody else get bothered by the term meds being used for OTC stuff? I always associate “meds” and “medication” with anything prescribed by a doctor. OTC I just call by whatever name it is, like ibuprofen or Tylenol. “meds” is vague because you don’t want to tell people what your medical condition is but it still implies that there is something more serious going on or it really is too hard to say the name of the medicine. Taking OTC isn’t really a big deal so there’s no reason to be vague.
It’s a signifier for a politico-economic concept, so yes. Third world is a similar signifier that also doesn’t really align with its original nor intuitive meanings. Semiotics is weird like that.
Either one can be used to signify countries from which resources and labor are extracted by the Global North or something along those lines. Do they find themselves richer or poorer due to global trade?
For example, Australia, in this context, wouldn’t be considered global south despite being in the southern hemisphere. Unless it was harshly colonized and became a resource trough for the USA and Europe, then its politico-economic position would change even though it obviously didn’t change geographically.
I used a flame thrower on the surfs that tried to set up a community in my town. Then I stabbed the survivors with one of those pointy sticks meant to pick up garbage.
most people just dismiss that, because they “already know” the answer
Maths teachers already know how to do Maths. Huh, who would’ve thought? Next thing you’ll be telling me is English teachers know the rules of grammar and how to spell!
and a two-sentence comment can’t convince them how and why it’s ambiguous
a solidus (/) shall not be followed by a multiplication sign or a division sign on the same line
There’s absolutely nothing wrong with doing that. The order of operations rules have everything covered. Anything which follows an operator is a separate term. Anything which has a fraction bar or brackets is a single term
most typical programming languages don’t allow omitting the multiplication operator
Because they don’t come with order of operations built-in - the programmer has to implement it (which is why so many e-calculators are wrong)
“.NET IDE0048 – Add parentheses for clarity”
Microsoft has 3 different software packages which get order of operations wrong in 3 different ways, so I wouldn’t be using them as an example! There are multiple rules of Maths they don’t obey (like always rounding up 0.5)
Let’s say we want to clean up and simplify the following statement … o×s×c×(α+β) … by removing the explicit multiplication sign and order the factors alphabetically: cos(α+β) Nobody in their right mind would remove the explicit multiplication sign in this case
This is wrong in so many ways!
you did multiplication before brackets, which violates order of operations rules! You didn’t give enough information to solve the brackets - i.e. you left it ambiguous - you can’t just go “oh well, I’ll just do multiplication then”. No, if you can’t solve Brackets then you can’t solve ANYTHING - that is the whole point of the order of oeprations rules. You MUST do brackets FIRST.
the term (α+β) doesn’t have a coefficient, so you can’t just randomly decide to give it one. It is a separate term from the rest Is there supposed to be more to this question? Have you made this deliberately ambiguous for example?
if the question is just to simplify, then no simplification is possible. You’ve not given any values to substitute for the pronumerals
(α+β) is presumably (you’ve left this ambiguous by not defining them) a couple of angles, and if so, why isn’t the brackets preceded by a trig function?
As it’s written, it just looks like a straight-forward multiplying and adding pronumerals except you didn’t give us any values for the pronumerals meaning no simplfication is possible
if this was meant to be a trig question (again, you’ve left out any information that would indicate this, making it ambiguous) then you wouldn’t use c, o, or s for your pronumerals - you’ve got a whole alphabet left you can use. Appropriate choice of pronumerals is something we teach in Maths. e.g. C for cats, D for dogs. You haven’t defined what ANY of these pronumerals are, leaving it ambiguous
Nobody will interpret cos(α+β) as a multiplication of four factors
as originally written it’s 4 terms, not 1 term. i.e. it’s not cos(α+β), it’s actually oxsxxx(α+β), since that can’t be simplified. And yes, that’s 4 terms multiplied!
From those 7 points, we can see this is not a real Maths problem. You deliberately made it ambiguous (didn’t say what any of the pronumerals are) so you could say “Look! Maths is ambiguous!”. In other words, this is a strawman. If you really think Maths is ambiguous, then why didn’t you use a real Maths example to show that? Spoiler alert: #MathsIsNeverAmbiguous hence why you don’t have a real example to illustrate ambiguity
Implicit multiplications of variables with expressions in parentheses can easily be misinterpreted as functions
No they can’t. See previous points. If there is a function, then you have to define what it is. e.g. f(x)=x². If no function has been defined, then f is the pronumeral f of the factorised term f(x), not a function. And also, if there was a function defined, you wouldn’t use f as a pronumeral as well! You have the whole rest of the alphabet left to use. See my point about we teach appropriate choice of pronumerals
So, ambiguity really hides everywhere
No, it really doesn’t. You just literally made up some examples which go against the rules of Maths then claimed “Look! Maths is ambiguous!”. No, it isn’t - the rules of Maths make sure it’s never ambiguous
IMHO it would be smarter to only allow the calculation if the input is unambiguous.
Which is exactly what calculators do! If you type in something invalid (say you were missing a bracket), it would say “syntax error” or something similar
force the user to write explicit multiplications
Are you saying they shouldn’t be allowed to enter factorised terms? If so, why?
force notation that is never ambiguous
We already do
but that would lead to a very convoluted mess that’s hard to read and write
In what way is 6/2(1+2) either convoluted or hard to read? It’s a term divided by a factorised term - simple
providing context that makes it unambiguous
In other words, follow the rules of Maths.
Links about various potentially ambiguous math notations
Spoiler alert: they’re not
“Most ambiguous phrases and notations in maths”
e.g. fx=f(x), which I already addressed. It’s either been defined as a function or as pronumerals, therefore nothing ambiguous
“Absolute value notation is ambiguous”
No, it’s not. |a|b|c| is the absolute value of a, times b, times the absolute value of c… which you would just write as b|ac|. Unlike brackets you can’t have nested absolute values, so the absolute value of (a times the absolute value of b times c) would make no sense, especially since it’s the EXACT same answer as |abc| anyway!
In-line power towers like
Left associativity. i.e. an exponent is associated with the term to its left - solve exponents right to left
People saying “I don’t know how to interpret this” doesn’t mean it’s ambiguous, nor that it isn’t defined. It just means, you know, they need to look it up (or ask a Maths teacher)! If someone says “I don’t know what the word ‘cat’ means”, you don’t suddenly start running around saying “The word ‘cat’ is ambiguous! The word ‘cat’ is ambiguous!” - you just tell them to look it up in a dictionary. In the case of Maths, you look it up in a Maths textbook
Because the actual math is easy almost everybody has an opinion on it
…and any of them which contradict any of the rules of Maths are demonstrably wrong
Most people also don’t know that with weak and strong juxtaposition there are two conflicting conventions available
…and Maths teachers know that both of them are made-up and not real things in Maths
But those mnemonics cover just the basics. The actual real world is way more complicated and messier than “BODMAS”
Nope. The mnemonics plus left to right covers everything you need to know about it
Even people who know about implicit multiplication by juxtaposition dismiss a lot of details
…because it’s not a real thing
Probably because of confirmation bias and/or because they don’t want to invest so much time into thinking about stupid social media posts
…or because they’re a high school Maths teacher and know all the rules of Maths
the actual problem with the ambiguity can’t be explained in a quick comment
Yes it can…
Forgotten rules of Maths - The Distributive Law (e.g. a(b+c)=(ab+ac)) applies to all bracketed Terms, and Terms are separated by operators and joined by grouping symbols
It’s only a matter of taste and how widespread a convention or notation is
The rules are in every high school Maths textbook. The notation for your country is in your country’s Maths textbooks
There are no arguments or proofs about what definition is correct
1+1=2 by definition (or whatever the notation is in your country). If you write 1+1=3 then that is wrong by definition
I found a lot of explanations online that were either half-assed or just plain wrong
And you seem to have included most of them so far - “implicit multiplication”, “weak juxtaposition”, “conventions”, etc.
You either were taught something wrong or you misremember it.
Spoiler alert: It’s always the latter
IMHO the mnemonics would be better without “division” and “subtraction”, because it would force people to think about it before blindly applying something the wrong way – “PEMA” for example. Parentheses, exponentiation, multiplication, addition
In fact what would happen is now people wouldn’t know in what order to do division and subtraction, having removed them from the mnemonic (and there’s absolutely no reason at all to remove them - you can do everything in the mnemonic order and it works, provided you also obey the left-to-right rule, which is there to make sure you obey left associativity)
parenthesis and exponents students typically don’t learn the order of operations through some mnemonics they remember them through exercise
That’s not true at all. Have you not read through some of these arguments? They’re all full of “Use BEDMAS!”, “Use PEMDAS!”, “It’s PEMDAS not BEDMAS!” - quite clearly these people DID learn order of operations through the mnemonics
trying to remember some random acronyms
There’s no requirement to memorise any acronym - you can always just make up your own if you find that easier! I did that a lot in university to remember things during the exam
they also state to “not use × to express a simple product”
…because a product is a Term, and to insert a x would break it into 2 Terms
The center dot also should not be used to mean a simple product
Exact same reason. They are saying “don’t turn 1 term into 2 terms”. To put that into the words that you keep using, “don’t use weak juxtaposition”
Nobody at the American Physical Society (at least I hope) would say that 6/2×3 equals one, because that’s just bonkers
Because it would break the rule of left associativity (i.e. left to right). No-one is advocating “multiplication before division” where it would violate left to right (usually by “multiplication” they’re actually referring to Terms, and yes, you literally always have to do Terms before Division)
÷ (obelus), : (colon) or / (solidus), but that is not the case and they can be used interchangeably without any difference in meaning. There are no widespread conventions, that would attribute different meanings
Yes there is. Some countries use : for divide, whereas other countries use it for ratio
most standards forbid multiple divisions with inline notation, for example expressions like this 12/6/2
Name one! Give me a reference! There’s nothing forbidding that in Maths (though we would more usually write it as 12/(6x2)). Again, all you have to do is obey left to right
Funny enough all the examples that N.J. Lennes list in his letter use
Something, something, Distributive Law (yes, some people use the wrong name, but in talking about the property, not the law, you’re knocking down a strawman)
The distributive property is just a property that applies to some operations
…and The Distributive Law applies to every bracketed term that has a coefficient, in this case it’s 2(1+2)
It has nothing to do with the order of operations
And The Distributive Law has everything to do with order of operations, since solving Brackets is literally the first step!
I’ve no idea where this idea comes from
Maybe you should’ve asked someone. Hint: textbooks/teachers
because there aren’t any primary sources (at least I wasn’t able to find any)
6÷2(3). If we follow the strong juxtaposition convention, we must
…distribute the 2, always
It has nothing to do with the 3 being inside parentheses
It has everything to do with there being a coefficient to the brackets, the 2
Those parentheses are only there, because
…it’s a factorised term, and the opposite of factorising is The Distributive Law
the parentheses do not force the multiplication
No, it forces distribution of the coefficient. a(b+c)=(ab+ac)
The parentheses are only there to make it clear that
…it is a factorised term subject to The Distributive Law
we are implicitly multiplying two separate numbers.
They’re NOT 2 separate numbers. It’s a single, factorised term, in the same way that 2a is a single term, and in this case a is equal to (1+2)!
With the context that the engineer is trying to calculate the radius of a circle it’s clear that they meant r=C/(2π)
Because 2π is a single term, by definition (it’s the product of a multiplication), as is r itself, so that should actually be written r=(C/2π)
When symbols for quantities are combined in a product of two or more quantities, this combination is indicated in one of the following ways: ab,a b,a⋅b,a×b
Incorrect. Only the first one is a term/product (not separated by any operators) - the last 2 are multiplications, and the 2nd one is literally meaningless. Space isn’t defined as meaning anything in Maths
Division of one quantity by another is indicated in one of the following ways:
Creates ambiguity since space isn’t defined to mean anything in Maths. Looks like a typo - was there meant to be a multiply where the space is? Or was there not meant to be a space??
The behaviour is intended and even carefully documented in the manual
…and yet still a bug (I saw at least one other person point this out to you)
A few years ago, there was a Microsoft feature intended for people in China, but people who weren’t in China were getting that behaviour. i.e. a bug. It was documented and a deliberate design choice for people in China, but if you weren’t in China then it’s a bug. Just documenting a design choice doesn’t mean bugs don’t happen. A calculator giving a wrong answer is a bug
weak juxtaposition is only used by old calculators
Based on the comments in the above video, the opposite is true - this problem first arose in '96
because they are scientific calculators.
So the person programming it is far more likely to need to check their Maths first - bingo!
TI (Texas Instruments) also has some calculators that use strong juxtaposition and some products that use weak juxtaposition
…and some that use both! i.e. some follow Terms but not The Distributive Law. As I said to begin with, these are 2 DIFFERENT rules, and you can’t just lump them together as one
evaluate 1/2X as 1/(2X)
Which is correct, as per Terms
while other products may evaluate the same expression as 1/2X from left to right
What you mean is they evaluate it as 1/2xX, since 1/2X and 1/(2X) are the same thing
it would be necessary to group 2X in parentheses
No, not necessary, since 2a=(2xa) by definition, alluded to in Cajori in 1928…
Sharp is a bit of an exception here, because all their other scientific calculators seem to
…follow all the rules of Maths, always. There’s something to be said for making sure you’re doing it right. :-)
Google uses the same priority for explicit and implicit multiplication
…and they will actually remove brackets I have put in and replace them with their own (“hi” to all the people who say you can fix any calculator by “just add more brackets” - Google doesn’t CARE what brackets you’ve added!)
Desmos and GeoGebra try to force the user into using fractions (which is a good design decision if you ask me)
It’s not, because a ÷ isn’t a fraction bar. They’re joining 2 terms into one and thus sometimes changing the answer
A lot of other tools like programming languages, spreadsheets, etc. don’t allow implicit multiplication syntax at all
It’s not that they don’t allow it, it’s that it’s not provided with the language by default in the first place! Most languages only provide you with some numbers, operators, and a few functions (like round), and it’s up to the programmer to implement the rest. Welcome to why there are so many wrong e-calculators
let you choose if you want weak or strong juxtaposition
…which is a red flag to not use that calculator!
This gives you more control about how you like the calculator to behave in these situations
I’m not sure it does. I’d have to switch on “strong juxtaposition” (the only kind there is) and see what else has been disobeyed in Maths. e.g. Google removing my brackets and adding different ones
Wolfram|Alpha only uses strong juxtaposition between named variables, but weak juxtaposition for everything else. This might seem strange and inconsistent at first but is probably the least surprising behaviour for most people
I find any exceptions to following the rules of Maths surprising! No, you can’t just make up your own rules
many textbooks, “a/bc” is intended to denote a/(bc)
a/bc=a/(bc) in every textbook
Wolfram Language, it means (a/b)×c
Welcome to “we’re gonna add brackets to what you typed in and change the answer”
a multiplication sign has been omitted
…then that means it’s not “multiplication” - it’s Terms and/or The Distributive Law. The “M” in the mnemonics refers literally to multiplication signs, nothing else
Multiplication and division have the same priority, they are “mathematically speaking” the same operation. This also applies to addition and subtraction. One is just the inverse function of the other
most children don’t become mathematicians later in life and if they do, they will learn all the other important stuff about the order of operations later
No, they won’t. Year 8 is the last time order of operations is taught, and they have been taught everything they need to know about it by then
it’s hard to pump so much knowledge into children and teenagers
…and yet have you not noticed that teenagers almost never get this wrong - only adults do
Using “PEMDAS” to argue about the order of operations in mathematics
…is a totally valid thing to do. The problem is people classifying Distribution (Brackets/Parentheses with a coefficient) as “Multiplication”, when there’s literally no multiplication sign
Math notations and conventions evolve exactly like natural languages
There is no definitive norm, standard or convention of notations and order of operations
You can find them in any high school textbook in your country (notation varies by country, but the rules don’t)
some words only appear in half of them (like “implicit multiplication by juxtaposition”)
“implicit multiplication” doesn’t appear in any Maths textbooks
sentences like “I saw the man with the telescope”, because it’s not clear if you saw him through the telescope or saw him holding (or looking through) a telescope
Yes it is clear (as I think I saw someone already point out here)
I saw the man with the telescope - the man has the telescope
I saw the man, with the telescope - I saw the man through a telescope
I saw the man through the telescope - I saw the man through a telescope
it should also be clear why there are no arguments or proofs for any side
But there are proofs! (There you go again with the “there is no…” red flag) Order of operations proof
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