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] 7 points 7 months ago* (last edited 7 months ago) (3 children)

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

[–] [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] 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] 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.

[–] SmartmanApps 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

[–] SmartmanApps -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.

[–] SmartmanApps 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 (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.

[–] SmartmanApps -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.

[–] SmartmanApps 2 points 7 months ago

My calculator says -2² = -4

That's correct