Question

What is limit?

Answer 1

Do you know what a infinite sequence is?

Answer 2

( I am only 14 years odl yet, And want to learn earlier :) )

Answer 3

hmm
I don2T know its turkish .. explain ?

Answer 4

Basically it's a function from the the natural numbers into any other set. (e.g. real numbers).
So for every number/position 1,2,3,... you have an element of your set. That's just what's meant by sequence. And infinite, because the natural numbers don't end, so neither does your sequence.
For example you could have a constant sequence 7,7,7,7,... or you could have the natural numbers themselve: 1,2,3,4,... or you could have 1/ all even numbers: 1/2, 1/4, 1/6, 1/8, ...
All those are infinite sequences.

Answer 5

ok i got it

Answer 6

Limits come to live, as you want to know how these sequences behave at infinity. If the limit of a sequence exists, the sequence tends more and more to that limit.
For example the last sequence there 1/2, 1/4, 1/6, ... goes to 0.
In more rigour terms you can say, that no matter how small an ε > 0 you choose, the sequence will eventually stay closer to the limit than that ε.

Answer 7

hmmm so how can we use these?

Answer 8

we do the process near of the "lim" keyword till the count under of it arives to the limit?

Answer 9

The most noted application is with derivations.
I guess you know about slope of straight lines of the plane.
For general functions, it is much more difficult to give a slope and of course it's value depends on the point you choose. So you start by drawing a secant on the function, which will cut the function graph at the points (x, f(x)) and (y, f(y)). Then you can calculate it's slope \[\frac{f(x)-f(y)}{x-y}\]. But that only exists for \(x \neq y\). So you have to take a sequence of x which tends to y and see where that quotient goes. That is the slope of \(f\) at the point \(x\).

Answer 10

ahh ok i got it

Answer 11

So well, there are two types of limits, to be fair. The one I showed you first was for a sequence, if you name your sequence \(a_1, a_2, a_3, \dots\) then you can write it as \[\lim_{n→∞}\;a_n\]
But then you can introduce another limit, for a function \(f\) (so maybe just a simple term) and write \[\lim_{x→x_0}\;f(x) = y\] which means that for any sequence that tends to \(x_0\) the function value tend to y:\[\forall (x_n)_{n=1}^∞: \left( \lim_{n→∞}\;x_n = x_0 \right)⇒ \left(\lim_{n→∞}\;f(x_n) = y\right)\]

Answer 12

kk^^ function f =??

Answer 13

f can be any function

Answer 14

ahh k ^^

Answer 15

so it does the process near of the "lim" till the squence comes to its limit (sorry for a bad english :( )

Answer 16

Yes, but there is no guarantee, that the process will succeed to lead to one particular number.
For the last part you also would like to have, that, as the x approaches \(x_0\) the function values approach \(f(x_0)\) but that must neither be the case. If it is, you say, f is continuous at \(x_0\)

Answer 17

hmmm k^^

Answer 18

I guess you can find a lot on it also on wikipedia ;-)

Answer 19

:-) ty much ^^

Answer 20

and can you help me in my other question?

Answer 21

Let's see.