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[-] SmartmanApps@programming.dev 1 points 2 years ago

We agree that the two situations are separate

Ok, that's a start.

but the first result is 4 ÷ a the second result is 4a

Exactly! So when a=2 then 4÷a=2, and 4a=8, which isn't the same thing. Welcome to why 2a and 2xa (and therefore also 2.a) aren't the same thing.

I use the dot as an expression of the same term rather than separate.

But that is incorrect. A dot is used for multiplication. i.e. it separates terms. If you use a . for 2.a, then you are writing the same thing as 2xa, not the same thing as 2a.

This is matter of my notational convention

Well, that's fine enough if you keep it to yourself, but don't use it in anything anyone else is going to read, or you're going to run into the issues I just pointed out

[-] SmartmanApps@programming.dev 1 points 2 years ago

That’s an after the fact justification

You got some sources with dates in them to show it was "after", and not, you know, before?

[-] SmartmanApps@programming.dev 1 points 2 years ago

Please see this section of Wikipedia on the order of operations

That section is about multiplication, and there isn't any multiplication in this expression.

The “math” itself might not be ambiguous, but how we write it down absolutely can be

Not in this case it isn't. It has been written in a way which obeys all the rules of Maths.

This is why you don’t see actual mathematicians arguing over which one of these calculators is correct

But I do! I see University lecturers - who have forgotten their high school Maths rules (which is where this topic is taught) - arguing about it.

it is not either calculator being wrong

Yes, it is. The app written by the programmer is ignoring The Distributive Law (most likely because the programmer has forgotten it and not bothered to check his Maths is correct first).

US - PEMDAS vs UK - BODMAS

Those aren't the rules. They are mnemonics to help you remember the rules

notice division and multiplication swapped places

Yes, that's right, because they have equal precedence and it literally doesn't matter which way around you do them.

you can’t actually do all of the multiplication and division at one time

Yes, you can!

Some are taught to simply work left to right

Yes, that's because that's the easy way to obey the actual rule of Left associativity.

we are all taught to use parentheses correctly to eliminate ambiguity

Correct! So 2(2+2) unambiguously has to be done before the division.

[-] SmartmanApps@programming.dev 1 points 2 years ago

go past past high school and this isn’t remotely true

But this is a high school Maths question, so "past high school" isn't relevant here.

[-] SmartmanApps@programming.dev 1 points 2 years ago

Mathematicians know wolfram is wrong

Woo hoo! I hadn't heard of anyone else pointing this out (rather, I'm always on the receiving end of "But Wolfram says..."), so thanks for this comment! :-) Now I know I'm not alone in knowing that Wolfram is wrong.

like claiming the world isn’t definitely round because some people argue its flat

OMG, I've run into so many people like that. They seem to believe (via saying "look, this blog says it's ambiguous too") that 2 wrongs make a right. No, you're both just wrong! Wolfram, Google, ChatGPT(!), the guy who should mind his own business, are all wrong.

Sometimes people are wrong

Yes, they are... and unfortunately a whole bunch of the time they're unwilling to face it and/or admit it, even when faced with Maths textbooks which clearly show what they said is wrong.

[-] SmartmanApps@programming.dev 1 points 2 years ago

they don’t typically write division inline like that

Yes we do.

But if you want to argue that Wolfram-Alpha’s equation parser is wrong go ahead

Wolfram-Alpha’s equation parser is wrong

[-] SmartmanApps@programming.dev 1 points 2 years ago

math is literally the only subject that has rules set in stone

Indeed, it does.

This example is specifically made to cause confusion.

No, it isn't. It simply tests who has remembered all the rules of Maths and who hasn't.

Division has the same priority as multiplication

And there's no multiplication here - only brackets and division (and addition within the brackets).

A fraction could be writen up as (x)/(y) not x/y

Neither of those. A fraction could only be written inline as (x/y) - both of the things you wrote are 2 terms, not one. i.e. brackets needed to make them 1 term.

The fact that some people argue that you do () first and then do what’s outside it means that

...they know all the relevant rules of Maths

look up the facts for yourself

You can find them here

your comment is just as incorrect as everyone who said the answer is 1

and 1 is 100% correct.

well they don’t agree on 0^0

Yes they do - it's 1 (it's the 5th index law). You might be thinking of 0/0, which depends on the context (you need to look at limits).

[-] SmartmanApps@programming.dev 1 points 2 years ago

you could easily make this more straightforward by putting parentheses around 8÷2

But that would be a different expression with a different answer (16 rather than 1). This is the mistake made by the programmer of the e-calc - treats it as though there's extra brackets there when there isn't.

[-] SmartmanApps@programming.dev 1 points 2 years ago

a(b) is a×b

a(b) is (a×b) - you can't remove brackets unless there is only 1 term left inside.

8/(2x4)=8/8=1

[-] SmartmanApps@programming.dev 1 points 2 years ago

They were right but for the wrong reason

As are you. There is no such thing as implicit multiplication - the actual relevant rules are Terms and The Distributive Law.

explicitly ambiguous

#MathsIsNeverAmbiguous #DontForgetDistribution

[-] SmartmanApps@programming.dev 1 points 2 years ago

This has been resolved by updating to VS 17.8.7 or 17.9

[-] SmartmanApps@programming.dev 1 points 2 years ago

Are you talking about the lack of indentation? I don't know why it does that. I tried using   with the same result. I'd fix it if I knew how!

Well, I just had an issue then here with   and eventually found backslash worked - I'll give that a go (not sure if I already tried it before).

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