Talk

(19 Posts)
irvine101 Thu 29-Oct-15 12:29:43

My ds asked me "is there such thing as -0 and +0, while doing some maths integers question. My initial reply was 0 is 0, there's no -0 or +0.
But I am not good at maths, so I started to wonder.
Is there -0 and +0 in mathematics?

I don't think so. I think it is the point in the middle where + turns into -

Like the Equator where N turns into S.

I only did maths to A level though. Perhaps 0 turns + and - at degree level

fredfredgeorgejnrsnr Thu 29-Oct-15 12:41:42

No signed zeros in maths.
There is in computing.

wanderings Thu 29-Oct-15 12:42:35

I don't think there's a +0 or -0; numbers are positive, zero or negative.

Mind you, the ancient Greeks weren't sure if zero actually existed, if I remember rightly.

irvine101 Thu 29-Oct-15 12:51:18

Thank you everyone!
I'm so glad we have MN.

mrz Thu 29-Oct-15 13:03:22

In most countries zero is neither positive or negative so the value of +0 is the same as -0

irvine101 Thu 29-Oct-15 13:14:06

Thank you mrz.
I can't do without MN!!!

catkind Thu 29-Oct-15 13:25:53

If you see - as an operator, then zero is unique in that -0=0. So you can write it as 0, +0 or -0 but it's all the same number.

irvine101 Thu 29-Oct-15 15:06:37

Thank you catkind

Zettina Thu 29-Oct-15 15:17:59

On the other hand . . . .

www.bbc.com/news/magazine-20559052

math.stackexchange.com/questions/1113709/is-zero-an-even-number

If you google "is zero odd or even", the consensus seems to be that it's an even number.

mrz Thu 29-Oct-15 15:27:44

As is -0 and +0 zettina

irvine101 Thu 29-Oct-15 15:54:23

Thank you Zettina, but it's getting too complicated for me...

Jux Thu 29-Oct-15 17:37:23

You don't want to start think about infinity, then, Irvine! It's a nightmare!

irvine101 Thu 29-Oct-15 17:50:59

No ! Absolutely not.

It can sometimes matter whether you approach zero from above or below, e.g. when taking limits. If you had a function f(x) that was

-1 for x<0
0 for x = 0
+1 for x>0

then its limit as x -> 0+ is +1 and the limit as x->0- is -1. The + and - attached to the zero just indicate the direction of approach to 0. In this case 0 is not a point of continuity and you might say this is expressed by writing that f(0+) is not the same as f(0) and that is not the same as f(0-). But this would be pretty advanced even for a further maths set, and limits are usually a uni topic. In ordinary arithmetic there is no sign attached to zero.

irvine101 Thu 29-Oct-15 21:45:14

Thank you roguedad, but it is getting way over my capacity. Only thing I understood was
"In ordinary arithmetic there is no sign attached to zero."

MN is like having a personal teacher! I'm very grateful.
Thank you again everyone!

I just noticed this was in the primary ed section. sorry for OTT reply.

Witchend Thu 29-Oct-15 22:01:17

That's for approaching zero as a limit rather than actually zero. Makes life more interesting considering it that way for some things, but perhaps not relevant for this discussion.

Approaching infinity (or minus infinity) is the way to consider that concept though as infinity is only a concept and not a number.

irvine101 Thu 29-Oct-15 22:13:41

My DS asked me about infinity before, but I can't even remember what I said.
"infinity is only a concept and not a number." is really good thing for me to remember.

I will copy and paste all the answers and make a note of it for future reference. Thanks again.

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