this post was submitted on 03 Apr 2024
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Science Memes

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submitted 7 months ago by [email protected] to c/[email protected]
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[–] [email protected] 2 points 7 months ago (1 children)

Unfortunately some calculators, such as Google's will ignore your brackets and put in their own anyway. You just gotta find a decent calculator in the first place.

[–] [email protected] 2 points 7 months ago (1 children)

It is also frustrating when different calculators have different orders of operations and dont tell you.

[–] [email protected] 3 points 7 months ago

It is also frustrating when different calculators have different orders of operations and dont tell you.

Yeah, but to be fair most of them do tell you the order of operations they use, they just bury it in a million lines of text about it. If they could all just check with some Maths teachers/textbooks first then it wouldn't be necessary. Instead we're left trying to work out which ones are right and which ones aren't. Any calculator that gives you an option to switch on/off "implicit multiplication", then just run as fast as you can the other way! :-)

[–] [email protected] 1 points 7 months ago

me using sbcl for everything

[–] [email protected] 4 points 7 months ago* (last edited 7 months ago) (1 children)

I recall that there is a myriad of memes of the form 'what is 4-2*3' under which there is always a never ending discussion of confidently incorrect dumbasses denying the existence of the multiplication before addition rule.

So your suspicion is at least not unreasonable

[–] [email protected] 1 points 7 months ago

Is the title a Requiem for a Dream reference?

[–] [email protected] 2 points 7 months ago

(> (explicit) (implicit))

[–] [email protected] 7 points 7 months ago* (last edited 7 months ago) (3 children)

My calculator says -2² = -4, so yeah...

[–] [email protected] 2 points 7 months ago

My calculator says -2² = -4

That's correct

[–] [email protected] 3 points 7 months ago (1 children)

I would never write -n². Either ‐(n²) or (-n)². Order of operations shouldn't be some sort of gotcha to trick people into misinterpreting you, it's the intuitive reading of a well constructed mathematical expression.

[–] [email protected] -2 points 7 months ago

Either ‐(n²) or (-n)². Order of operations shouldn’t be some sort of gotcha to trick people into misinterpreting you

It isn't. With ‐(n²), n² is already a single term, so the brackets aren't needed.

[–] [email protected] 7 points 7 months ago (2 children)

Isn't the "-" order of operations the same as a multiply ? I think I learned powers take priority over the "-" so your calculator would be right.
But either way if it can cause confusion you should use parentheses.

[–] [email protected] 1 points 7 months ago

I think I learned powers take priority over the “-”

Yes, Exponents is the 2nd-highest precedence (after Brackets) - BEDMAS.

[–] [email protected] 3 points 7 months ago (2 children)

Every calculator I've used has separate negative and subtraction keys for this purpose. There is no order of operations to follow, it's just a squaring a number

[–] [email protected] -1 points 7 months ago

it’s just a squaring a number

The number being squared is 4, unless you put (-4)², otherwise it's 4² with a minus sign.

[–] [email protected] 3 points 7 months ago* (last edited 7 months ago) (1 children)

I learned negative as being a separate operation where we need to apply the order of operations. I think it was something like : -2 is a diminutive for -1x2 so it uses the order of operations of a multiplication.
My calculator is the official one used in schools in France (ti-83 premium ce) and it says -2^2 = -4 with the negative key. I don't think it would make a mistake in such a simple concept.

But whatever these concepts can change depending on the field, country, level of education. What I mean is : it's unclear, so use parentheses. So (-2)^2 or -(2^2) are the correct ways to write it.

[–] [email protected] 2 points 7 months ago

I think it was something like : -2 is a diminutive for -1x2

Correct. Things that are usually left out of Maths expressions are plus signs, ones as multipliers/indices, and un-needed brackets. e.g. I could more fully write this as -1(4)², but that just simplifies to -4²

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