(-) precedence

[Matt Agajanian]

(12-08-2022 01:47 PM)jhallen Wrote:  

(12-08-2022 01:30 PM)Thomas Okken Wrote:  -2^2 = -4, that is the only correct answer.

I know that, for some reason, among computer types, there is this idea that unary minus should have higher precedence than exponentiation, but that is not how it works in the commonly used mathematical notation.

Note those parentheses around the -1. Those are not redundant.

This is true in mathematical notation because subtract and negate use the same symbol. On a calculator, we have two different keys, so this limitation is not required. EOS is really FORTRAN anyway (i.e., squeezing math onto a single teletype or punched-card line), no mathematician writes equations that way.. so why conform on this specific point?

On HP-33s, when you type 2 (+/-) x^2, it displays (-2)^2: very nice for clarity.

One more argument: it's confusing when students are learning substitution that:
f(-1) = x^2 gives a different answer than -1^2


Anyway, it's interesting that TI tried it with TI-68 and Galaxy-67.

Now I'm confused. How can it be intuited that the - is applied to the entire
2x2, thus -4 and the - is not exclusive to the 2, thus -2? Or are you saying that unary minus is lower in precedence (i.e. 2*2, then negate the answer, 4)?