Difference between revisions of "Sequence"

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A '''sequence''' is an ordered list of terms.  Sequences may be either [[finite]] or [[infinite]].  In [[mathematics]] we are often interested in sequences with specific properties.
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A '''sequence''' is an ordered list of terms.  Sequences may be either [[finite]] or [[infinite]].  In [[mathematics]] we are often interested in sequences with specific properties, the [[Fibonacci sequence]] is perhaps the most famous example.
  
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==Definition==
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A '''sequence of real numbers''' is simply a function
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<math>f:\mathbb{N}\rightarrow\mathbb{R}</math>
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The numbers <math>f(n)</math> are often denoted as <math>a_n</math> and the set <math>f(\mathbb{N})</math> is denoted as the 'sequence' <math>\left\langle a_n\right\rangle</math>
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==Convergence==
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The notion of 'converging sequences' is often useful in [[Analysis|real analysis]]
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Let <math>\left\langle a_n\right\rangle</math> be a real valued sequence
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Let <math>L\in\mathbb{R}</math>
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We say that '<math>\lim_{n\rightarrow\infty}a_n=L</math>'
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or '<math>\left\langle a_n\right\rangle</math> converges to <math>L</math>' if and only if
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<math>\forall\epsilon>0</math>, <math>\exists\M\in\mathbb{N}</math> such that <math>n>M\implies |L-a_n|<\epsilon</math>
  
 
== Resources ==
 
== Resources ==
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* [[Arithmetic sequence]]
 
* [[Arithmetic sequence]]
 
* [[Geometric sequence]]
 
* [[Geometric sequence]]
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* [[Bolzano-Weierstrass theorem]]
  
 
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Revision as of 04:39, 23 February 2008

A sequence is an ordered list of terms. Sequences may be either finite or infinite. In mathematics we are often interested in sequences with specific properties, the Fibonacci sequence is perhaps the most famous example.

Definition

A sequence of real numbers is simply a function

$f:\mathbb{N}\rightarrow\mathbb{R}$

The numbers $f(n)$ are often denoted as $a_n$ and the set $f(\mathbb{N})$ is denoted as the 'sequence' $\left\langle a_n\right\rangle$

Convergence

The notion of 'converging sequences' is often useful in real analysis

Let $\left\langle a_n\right\rangle$ be a real valued sequence

Let $L\in\mathbb{R}$

We say that '$\lim_{n\rightarrow\infty}a_n=L$'

or '$\left\langle a_n\right\rangle$ converges to $L$' if and only if

$\forall\epsilon>0$, $\exists\M\in\mathbb{N}$ (Error compiling LaTeX. Unknown error_msg) such that $n>M\implies |L-a_n|<\epsilon$

Resources

See Also

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