pouët.net

Thank you. Nice useful table you've got there broderik.

1) y-prime-t
2) plus-minus

"boring math stuff"

this is no where near boring math stuff

alright.. I majored in math and generally I heard "f at x".. but I do have a tendency to automatically translate what I'm hearing into what I want it to be :)

Maybe I'm just thinking of it a bit differently. What would you say for f(1)? Would you seriously say "f of 1"? I more often think of the x in f(x) as a placeholder that could be anything.. and so, f(x) is potentially a value.. but if you were talking about a function f(x) over the whole domain, I could go along with "f of x".

hmm, I see how that could be "f at 1". I'd still say "f of 1" in most cases.

In spanish, it gets worse.

You'd say "f de x" (which translates to "f of x"), but in all cases (at least that's how i learned it), for f(1) you'd say something ass-long like "f de x para x igual a 1" (f of x for x equals 1).

In a context though, one would just say "f 1" or "f x" :-)

Idiot! Can't you see this topic is
A) Quite interesting
B) As much a question of linguistics as it is a question of mathematics.

Oh, and it does not really matter WHAT you call it as long as people know what you're trying to say. :-P

What you're saying is that spanish speakers can guess variable names! :O

bigcheese, i'd say "f-x at 1"
i see it like this:

f(x) = "f-x"
f'(x) = "f-prime-x"

f(1) = f(x)|x=1 = "f-x at 1"

And yes. you can basically call it whatever you want. But my head thinks "f of x" like "f o x" ie f(x(y)).
However, I'd say it doesn't matter since you will need to have it written down anyways since mathematical notation is not a science.

stefan:
Yeah, I agree it can be called what you want. There's sometimes benefit to thinking about what to call things -- it makes you question what you're doing and clear some things up in your mind. And in certain circumstances, it's nice if you can be clear enough for someone to be able to record what you're saying on paper if you wish. Ultimately though, it's done on paper.
I think it's also okay to say "f of x" for f(x) sometimes, and "f at x" for f(x) at other times, to emphasize the way you're thinking in the situation. Expressing some subtlety is okay. Personally, I'm not a big fan of saying "f-x" since it's got some strange time sensitivity that I usually don't use at all.. though I suppose it's got the benefit of being standard across languages.

and I had the same concern about "f o x" ie f(x(y)).

I mean, "f of x" makes me think somewhat of "f o x".

Ok. I don't like "f at x" because because it somehow suggests to me that f is well defined. f-x or even f of x suggests is a function depending on a variable x that can be well defined but doesn't have to be. For instance when you are lazy you can say "f-inf" (in practice we tend to do that a lot) but saying "f at inf" sounds silly.

but it's appropriate that f at inf sounds somewhat silly, because it is :)

I guess "f of x" emphasizes the function.. and its properties.. almost as if you're emphasizing its code. "f at x" puts emphasis on values that come from it, and alludes to visualization of points along the graph. I feel like either one has its place. "f-x" is sort of.. well, that's about how much meaning you get when it's written on paper, so it's safe. I feel that it's not very expressive, but then again, you don't necessarily want to pigeonhole the listener into thinking about it in the same way as yourself anyway.

let me repeat it once more. There are different scenarios:

a) you are reading math notation. Then read "f(1)" as "ef one", because that's the simplest, and that's what people actually say. Proper programming languages, like Haskell, even have corresponding notation, and write "f 1" as well.

b) you try to explain it to somebody. In that case, say "[the function] ef evaluated at one" or something like that; but most definitely no "of".

stefan and anes won half a point each, for being almost right. Thread closed.

Sometimes putting no word between the terms is used for multiplication. (eg. "f(x) = xy" or "f(x) = x(y)" or "fx = xy", etc.). So there are other conventions involved in making it less ambiguous. Ideally you want to reserve letters and symbols for their usual use to avoid this confusion, but math is used in a lot of different fields.. so it doesn't always turn out that way. Use whatever works for you in your circumstances and don't let some supposed 'best' way make you think otherwise.

it depends a lot on whether people are known to your function and it's printed huge on a bigscreen you're standing in front of, or whether you'
re on the phone with some math guru student friend who didn't even take the subject you're talking about.

either way, i disagree with what you said that y'(t) is bad notation; i had not even considered that i could mean a derivative function. i guess it all depends on what you're doing; i.e. calculus or computer science. they've pretty differing notation standards.

In case someone else reading the bottom of this thread assumes I'm the one who said it was bad notation -- it was xernobyl :) I assumed it was just a new variant of y too.

sqrt(1): square root of one
cos(pi): cosine of pi

I'm not saying it's the best choice (there's no best choice), I say it fits more than you assume :)

The notation of derivative is decided by whether you're a Newtonian or a Leibnizist.

huh? what?

ooh you meant cos pi.

anes: That's interesting. I never thought of it that way. I often say "root 1" and "cos pi" ;) but I would say "cubed root of 1" rather than "cubed root at 1".. and I can now see the reasoning behind say "the f of 1" or "f of 1".

blala: Nice of you to state some "truths" about math notations, since there obviously are none. All my math books and all my math teachers have been using different notations (usually a mix of well known or some not so well known). Thats why all math books tend to start with "this is how i will write this and that". When it comes to speak i would say it's even more vague than in written form.

The of-at-or-- debate is rather useless since it really depends on the subject. When you are discussing F(inf) or Sqrt(2) you tend to use a more abstract way of saying it even if you actually say it more directly (F-inf or square root-2). However when you are looking at a discrete function and want to have its value you would often say F at 300 or F 300 rather than F of 300.

I guess its all about if you look at the function as a graph or just as a function, hell it could even be random with a weighted parameter. In that case it wouldn't actually be wrong to say "f of x" since it could be a weak definition.

Oh and I forgot. We are all lazy mother fuckers who want to say as much, or write as much with a minimum amount of words/characters.

Now.. Lets start the discussion about:

or or or maybe you prefer something like or or
or why not the grammar correct
Oh. Can we have a [latex] tag? ;-)

"In that case it wouldn't actually be wrong to say "f of x" since it could be a weak definition."
would be "In that case it would actually be wrong to say "f of x" since it could be a weak definition."