# Do Zero and infinity break laws?

1. Apr 8, 2008

### ahmedhassan72

Does any formula gives invalid results at infinity or zero compared to other values in the formula????
I tried as an example some calculus at normal values gives answers and at infity and zeros the rule is broken....
I think it is a must to formulate 0 with infinity and i don't know how....

2. Apr 8, 2008

### HallsofIvy

Why is this posted under "physics"?

Exactly what do you mean by "invalid" results? There are many formulas that give values for other numbers but not at zero or as the variable goes to infinity (not "at infinity" since formulas are only defined for number and infinity is not a number).

f(x)= 1/x is defined for all numbers except x= 0. f(x)= x itself is not defined as x goes to infinity. But there is nothing special about 0. The function f(x)= 1/(x-a) is not defined at x= a and a can be any number.

Perhaps I am misunderstanding your question. I certainly have no idea what you mean by "formulate 0 with infinity".

3. Apr 8, 2008

### ahmedhassan72

yes i mean near to zero or near to infinity as you are talkin about meters from 1 to 10 and put 10^-100 in an equation or put 10^100 in the same equation not exactly 1/x but many things are violated at numbers near zero or infinity

4. Apr 8, 2008

### ahmedhassan72

If we knew what it was we were doing, it would not be called research, would it?

Insanity: doing the same thing over and over again and expecting different results.

Albert Einstein

I think I knew that before finding these quotes....thanks

5. Apr 8, 2008

### HallsofIvy

Absolutely not! When doing research you do not know what results you will get but you must know what you are doing! I do agree that reasoning on the basis of facts is difficult- you go to all that work to determine what the facts are! But if you want anyone to pay attention to you, you had better start doing the work.

6. Apr 8, 2008

### Hootenanny

Staff Emeritus
I would like to add a little something here, which is that one also should consider the physical relevancy of any variable going to zero. For example, the Coulomb interaction may be written,

$$\underline{F} = K\frac{Qq}{r^2}\underline{\hat{r}}$$

which exhibits the behavior that I believe you describe. Here r represents the distance between two charges (could be bodies or points). However, one must ask is it physically meaningful to say the distance between to charged bodies, even point charges, is zero? How can this happen physically?

7. Apr 8, 2008

### will.c

If they are the same charge, in which case the coulomb interaction it exerts on itself is undefined, just like a number divided by zero.

8. Apr 8, 2008

### dst

Wouldn't it be sensible to avoid any ridiculous 1/n scenarios by just limiting the minimum distance to 1, i.e. "one planck length" or some other?

9. Apr 8, 2008

### ehj

dst, if you think that resembles reality any better, sure.. But I think you gotta show that first :)

10. Apr 8, 2008

### vertices

as my tutor always says "the physics is just in the boundary conditions, the rest is just maths". Infinities are almost always unphysical.

11. Apr 8, 2008

### dst

Well it makes very little sense to say anything can be in absolute contact since this is a generalisation of classical physics - we are talking about the very force that is responsible for "contact" to be defined so it makes little sense otherwise. If we're talking about a sphere then you can denote the surface to be at distance "1" and then it makes sense to say that for point particles you cannot have a distance below that, since it is essentially meaningless. Oh, and it gives a limit to the force as well - F = kQq.

12. Apr 8, 2008

### Hootenanny

Staff Emeritus
That was indeed my point, one should consider whether such situations are physically meaningful.

13. Apr 8, 2008

### ahmedhassan72

Firstly ,I would like to thank all for helping.

Just in the coloumb formula put r =10^1000000 or =10^-1000000 what it will give you and how is that described in nature so that the rule is incomplete it is just applied at certain intervals no more no less.....
So my own opinion is that since zeros and infinities exist in nature therefore you don't have to observe everything then find that most formulas are not applied at zero and infinity....So the problem is in the zero and infinity if you can make something that gets all number,zeros,and infinity in one thing so that if you observed a phenomena in nature and formulate it to normal values it could be applied also to zero and infinity....

There are many other things I can do if I just want others to pay attention to me ....helping others is better...and that's all

Hallsoflvy : if you read my post of light carefully you will find that it has something about zero and infinity and that the ratio i assumed can't be recognized except in certain limit and in certain conditions...and i just observed in my way that when you are in a car near objects move against you and far objects move with you??????

Stupidity is to see others stupid.God created all minds.

Last edited: Apr 8, 2008
14. Apr 8, 2008

### chroot

Staff Emeritus
So it's somehow deeply significant to you that the expression 1 / x becomes indeterminate when x = 0. Is it also deeply significant to you that the expression 1 / (x-2) becomes indeterminate when x = 2?

http://en.wikipedia.org/wiki/Parallax

This is nothing novel.

- Warren

15. Apr 8, 2008

### dst

I was of the impression that any physical law except say, that which describes relations between dimensionless constants is also pointless to declare as "fundamental" since it's all inductively derived. To see deep significance in 1/0 for any physical reason is hence not really a valid line of thought.

Are there formulae linking dimensionless parameters, by the way?

16. Apr 9, 2008

### Hootenanny

Staff Emeritus
How do you know that the Coloumb interaction is violated at these distances? Do you think it's possible to make observations at these distances?
As has been said previously, infinity is not a number.

17. Apr 9, 2008

### ahmedhassan72

sorry,but infinity is a number if i tell you an equation that deals with number from [-10,10] and i put 10^(10^10) or 10^-(10^10) by that method you can make one of two 1-find that the rule is broken
or 2-explain that in nature
the force affecting a wire in magnetic field=BIL and magnetic field of a wire =44/7*10^-7*I/d
so that if you put a very very thin wire at a distance =10^-(10^10) from another wire each wire is one meter carrying one ampere current each therefore force affecting the wire=ma and assume the mass of the wire is 1 therefore a will be 10^(very large number)nearly infinity so that theoretically after nearly o time the wire exceeds the speed of light.........

YOU WILL SAY THAT IS IMPOSSIBLE.....

YES,but you can assume that a thick wire, as an example i am not accurate ,is divided to n wires moving with v and so on so you can describe nature according to zero and infinity............

18. Apr 9, 2008

### Gost_D

-As well as Zero is not a number also...

19. Apr 9, 2008

### ahmedhassan72

I was violated for telling that infinity is a number .but i think i said that you put a number refers to infinity in a formula. cm and m and i put 10^1000 km what will happen,that's all..try it in any formula will find results that don't refer to our observed reality so i think it is one of two whether that every physical formula cannot be explained at any conditions or you can just explain new phenomenas by these limits of the formulas...

20. Apr 9, 2008

### Hootenanny

Staff Emeritus
You've completely lost me now. What is your point?