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No change in size ,  03:23, August 17, 2008
Function should be first. It is more fundamental, even if it might be considered harder.
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The concept of the '''limit''' is the cornerstone of [[calculus]], [[analysis]], and [[topology]].  At the simplest intuitive level, the limit of a function at a point is the value that the function "approaches" as its argument "approaches" that point.  As we will see, that is an unsatisfactory definition, and a much more careful definition is required.
 
The concept of the '''limit''' is the cornerstone of [[calculus]], [[analysis]], and [[topology]].  At the simplest intuitive level, the limit of a function at a point is the value that the function "approaches" as its argument "approaches" that point.  As we will see, that is an unsatisfactory definition, and a much more careful definition is required.
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==Limit of a Sequence==
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Let <math>(a_n)_{n\in N} = (a_1, a_2, a_3, ...)</math> be a [[sequence]] of [[real number]]s. We say that this sequence has a limit <math>a</math>, i.e.,
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<math>
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\lim_{n\to \infty} = a,
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</math>
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if for any <math>\varepsilon > 0</math>, there exists a number  <math>N</math>, such that
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<math>
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|a_n - a| < \varepsilon</math> for every <math>n > N</math>. Intuitively, this means that if you take  an [[interval]] as small as you like, [[center]]ed at the limit point, then most - i.e., all but a finite number - of the points of the sequence are in that interval.
      
==Limit of a Function==
 
==Limit of a Function==
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We still haven't proved that the limit is actually 1.  We just gave some accurate calculations strongly suggesting that it is.  In fact it is, and the proof requires a few theorems about limits, [continuous function]]s, and the [[exponential]] and [[natural logarithm]] functions.
 
We still haven't proved that the limit is actually 1.  We just gave some accurate calculations strongly suggesting that it is.  In fact it is, and the proof requires a few theorems about limits, [continuous function]]s, and the [[exponential]] and [[natural logarithm]] functions.
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==Limit of a Sequence==
 +
Let <math>(a_n)_{n\in N} = (a_1, a_2, a_3, ...)</math> be a [[sequence]] of [[real number]]s. We say that this sequence has a limit <math>a</math>, i.e.,
 +
<math>
 +
\lim_{n\to \infty} = a,
 +
</math>
 +
if for any <math>\varepsilon > 0</math>, there exists a number  <math>N</math>, such that
 +
<math>
 +
|a_n - a| < \varepsilon</math> for every <math>n > N</math>. Intuitively, this means that if you take  an [[interval]] as small as you like, [[center]]ed at the limit point, then most - i.e., all but a finite number - of the points of the sequence are in that interval.
    
[[category:mathematics]]
 
[[category:mathematics]]
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