What is the "opposite" of infinity Watch

gradjobplease
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Is it negative infinity or zero?
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Alpha-Omega
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Interesting question. Hmmm.... I think it would be zero. Since infinity represent being limitless while zero is complete absence.
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hrickards
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http://mathforum.org/library/drmath/view/63366.html Poses the question, and although it doesn't directly answer it does discuss it indirectly.
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Picnic1
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To my untrained (past A-level) mathematical mind:

If we allow negative numbers to exist then it should be negative infinity.

Then if I said what is the opposite of 4' the only thing you could say is 'minus 4'.
So that makes the opposite of 0 to still be 0 and the opposite of infinity to be minus infinity.

If we don't allow negative numbers to exist then the opposite of infinity should be 0 and vice versa.
Then the opposite of 4 would be infinity minus 4 presumably.
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james.h
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The problem here lies in the vague wording of the question.
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doggyfizzel
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Not sure what you mean,

positive infinity and negative infinity

Infinitely large and infinitesimally small

Maybe that helps
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Josh_Dey
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I don't know. Zero?
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thegoodthebadandtheTom
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(Original post by gradjobplease)
Is it negative infinity or zero?
Infinitesimality - infinitely small/negligible. Closest thing I can think of :cool:
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there's too much love
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(Original post by Picnic1)
To my untrained (past A-level) mathematical mind:

If we allow negative numbers to exist then it should be negative infinity.

Then if I said what is the opposite of 4' the only thing you could say is 'minus 4'.
So that makes the opposite of 0 to still be 0 and the opposite of infinity to be minus infinity.

If we don't allow negative numbers to exist then the opposite of infinity should be 0 and vice versa.
Then the opposite of 4 would be infinity minus 4 presumably.
I'm confused, why is the opposite of 4 minus 4?

Isn't it a case surely of asking whether it's possible for there to be an opposite of any number?
Isn't it like asking what the opposite of A is?
It could be B, C etc.

Wouldn't the correct thing not be -4 but instead ~4 (taken from formalized logic). That is, the opposite of 4 is not 4.
So anything that isn't 4 is the "opposite" of 4, so long as isn't "it". No?
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mauvetard
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zero?
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soutioirsim
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I also think zero.

But what happens if you have "0 x infinity". Because then you have something infinitely small multiplied by something infinitely big.

I kinda thought 0 = \frac{k}{infinity} would be true for a constant "k".
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Nashy19
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Infinitesimal, as in the infinitely small instead of the infinity large.
Or nothing (zero) as oppose to everything (infinity).

Depends whether you want the opposite end of the scale or the opposite of the scale itself.
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boromir9111
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eerrmmm.....finite?
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matt608
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But what's the difference between negative infinity and positive infinity? Surely there is none, so they are the same thing, not opposites.

Zero makes more sense, but still if zero is the opposite of infinity then with this zero there can be no potential for 1 (or anything else) which means if zero is the opposite of infinity then there is only zero, and if there is only zero then that zero is in effect infinite...

I think "finite" is the best answer seeing as infinity is a concept not a number... although numbers are just concepts too

:s
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hasan4life
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its zero and why everyone posting long essays on it
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there's too much love
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(Original post by matt608)
But what's the difference between negative infinity and positive infinity? Surely there is none, so they are the same thing, not opposites.

Zero makes more sense, but still if zero is the opposite of infinity then with this zero there can be no potential for 1 (or anything else) which means if zero is the opposite of infinity then there is only zero, and if there is only zero then that zero is in effect infinite.
See I think finite here.

The opposite of infinity is surely, simply, not infinity. So anything that is not infinity is the opposite.
In the same way that the opposite of 4 is ~4 (not to be confused with -4).

See my previous post for why I think that. Bare in mind I don't have a grounding in math, I just think the use of the word opposite here is queer, and I know infinity is either non-existence or an irrational number or whatever.
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there's too much love
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(Original post by hasan4life)
its zero and why everyone posting long essays on it
Surely it could also be, 1, 2, 3, 4, 5, 6 etc.
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mabrookes
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(Original post by Picnic1)
To my untrained (past A-level) mathematical mind:

If we allow negative numbers to exist then it should be negative infinity.

Then if I said what is the opposite of 4' the only thing you could say is 'minus 4'.
So that makes the opposite of 0 to still be 0 and the opposite of infinity to be minus infinity.

If we don't allow negative numbers to exist then the opposite of infinity should be 0 and vice versa.
Then the opposite of 4 would be infinity minus 4 presumably.
Infinite is not actually a number though, just a concept. Wouldn't the opposite just be finite?
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there's too much love
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(Original post by Picnic1)
Well I suppose that it could be argued that the opposite of 4 is 0.
The opposite of 'there is a greenhouse' would be 'there is no greenhouse' (nothing, unless further information is given as to there being something else there in its place).

So the opposite of '4' is 'no 4' (zero, unless further information is given as to there being something else there in its place)

On the other hand, you could say that the opposite of 'You have given me 4 things' is not just 'You haven't given me 4 things' but 'I have given you 4 things'.
So the opposite of 4 would be -4 there.

In other words- no conclusion as to what is right.
Well half my point is the question doesn't make sense.
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Kasc
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Numbers don't mathematically have an opposite, furthermore it serves no purpose for numbers to have an opposite (hence why they don't).
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