whats the deal with infinity in mathematics?

Answer 1

Many things in mathematics are made up to explain things. Irrational numbers (which cannot be defined as the ratio of integers), for example, were needed in order to define things like the circumfrence of a circle.

Here is a nice write-up on infinity:
http://news.bbc.co.uk/2/hi/programmes/documentary_archive/5349364.stm

Answer 2

The "deal" is that infinity is ill defined. Even mathematicians can argue about its characteristics and what it means.

The problem is that infinity is more a philosophy or concept than it is a number. For example, if I try to treat infinity as a number, what is this: infinity + 1 = ? As a number, we'd have infinity + 1 = infinity or 1 = infinity - infinity = 0, or 1 = 0...ooops...can't treat infinity as a number, at least real numbers like most of us are used to. (There are imaginary numbers where things get really weird.)

Unfortunately there are times in math (and the sciences using math) where infinity seems to be appropriate. N/0 = infinity, for example; where N is any number <> 0. If we rewrite N/0 as N/n with n --> 0, we can show that, as n approaches 0, N/n --> M a very big number that becomes unbounded at n = 0. it's that unbound part that we call infinity.

I've heard is said that Einstein once said to the effect "The only thing more puzzling than an infinite universe is a finite one...what would be on the other side?" So sometimes the concept (not a number) of infinity is a good thing.

Answer 3

it's perfectly plausible, it's merely to show the pattern of movement for a function that is ever continuous. Likewise it aids in determinig rates of different functions in comparison to each other. True x^2 is reaching positive and negative infinty alike to x but x^2 is doing it twice as(reaching infinity) fast than x. It is travelling twice as fast in a continuous manner. Likewise infinty +1 is faster than merely infinty, x+1 travels faster therefore in comparison to x. This helps tremendously in sciences and other branches. For example say a projectile is known to have a rate at x^2 and is travelling in this curve such that it will collide with another projectile travelling in a linear x, then we know that the x^2 projectile will be travelling at a higher rate than the projectile travelling in a function x considering x is a constant velocity for both projectiles.

Answer 4

Infinity in math shows how far something goes. It helps in solving for domain and range, and also helps in limits.
for examle, look at the domain for y=x^2. It travels from negative infinity to positive infinity. Without using these words, there is no other way of expressing the domain.

Answer 5

well it doesn't matter much but you know for things like
What might x be if x is a n integer and x < 3
so x could be {2,1,0,-1,-2....to minus infinity}
otherwise you wouldn't be able to answer the question.

Answer 6

It simply says it is not limited in size. It is undefined. In practical terms it means give me the largest number you can think of and I'll add 1 to it and give you a bigger one, etc etc etc

Answer 7

It's just a theoretical concept to show that numbers go on forever. No matter how high you can count, there's always one more number.

Answer 8

Men

Answer 9

Because in the universe there are infinite possibilities!

Answer 10

Tan90 = infinity ;)