Limit proof on Sequence Convergence

In summary, a limit proof on sequence convergence is a mathematical technique used to determine the behavior of a sequence as its terms approach a certain value, known as the limit. To prove that a sequence converges to a specific limit, it must be shown that for any small positive number, there exists a corresponding index of terms in the sequence after which all terms are within that small positive number of the limit. A sequence can only converge to one limit, and if it has multiple limits, it is considered to be divergent. The difference between a convergent and a divergent sequence is that a convergent sequence approaches a specific limit while a divergent sequence does not. Common methods used in limit proofs on sequence convergence include the formal definition of convergence
  • #1
Bipolarity
776
2
Consider a sequence [itex] \{ a_{n} \} [/itex].

If [tex] \lim_{n→∞}a_{n} = L[/tex] Prove that [tex] \lim_{n→∞}a_{n-1} = L [/tex]

I am trying to use the Cauchy definition of a limit, but don't know where to begin. Thanks.



BiP
 
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  • #2
Start by writing the definitions of

[tex]\lim_{n\rightarrow +\infty}{a_n}=L[/tex]

and

[tex]\lim_{n\rightarrow +\infty}{a_{n-1}}=L[/tex]
 

Related to Limit proof on Sequence Convergence

1. What is a limit proof on sequence convergence?

A limit proof on sequence convergence is a mathematical technique used to determine the behavior of a sequence as its terms approach a certain value, known as the limit. It involves showing that the terms of the sequence get closer and closer to the limit as the index of the terms increases.

2. How do you prove that a sequence converges to a specific limit?

To prove that a sequence converges to a specific limit, you need to show that for any small positive number, there exists a corresponding index of terms in the sequence after which all terms are within that small positive number of the limit. This can be done using the formal definition of convergence or through other convergence tests such as the squeeze theorem.

3. Can a sequence converge to more than one limit?

No, a sequence can only converge to one limit. If a sequence has multiple limits, it is considered to be divergent.

4. What is the difference between a convergent and a divergent sequence?

A convergent sequence is one that approaches a specific limit as the index of the terms increases, while a divergent sequence does not approach any specific limit. Divergent sequences can either have terms that increase or decrease without bound, or have terms that oscillate between different values.

5. What are some common methods used in limit proofs on sequence convergence?

Some common methods used in limit proofs on sequence convergence include the formal definition of convergence, the squeeze theorem, and the monotone convergence theorem. Other techniques, such as using algebraic manipulations or the ratio test, may also be useful in certain cases.

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