Is the Limit of a Convergent Sequence in [0,1]?

Let N be such that for n> N, |a_n- L|< \epsilon. Then for n> N, a_n< L+ \epsilon so that a_n< L + |L|/2= (L+ L)/2= 2L/2= L. Also, for n> N, a_n> L- \epsilon so that a_n> L- (L-1)/2= (L- L+ 1)/2= 1/2. But this means that for n> N, a_n is not in [0, 1], contrary to the hypothesis. So, our original assumption that L was not in [
  • #1
ptolema
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0

Homework Statement



suppose that {an} is a convergent sequence of points all in [0,1]. prove that lim an as n-->[tex]\infty[/tex] is also in [0,1]

Homework Equations



for all[tex]\epsilon[/tex]>0, [tex]\exists[/tex] a natural number N such that for all natural numbers n, if n>N, then absolute value(an-L)<[tex]\epsilon[/tex]

The Attempt at a Solution


i messed with the limit a lot, but the furthest i could get was that [0,1] was a subset of (-[tex]\epsilon[/tex],1+[tex]\epsilon[/tex]), which contains L (the limit). can someone shed some light on this?
 
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  • #2
Suppose L were NOT in [0, 1]. Then either L< 0 or L> 1.

If L< 0, let [itex]\epsilon= |L|/2[/itex].

If L> 1, let [itex]\epsilon= (L-1)/2[/itex].
 

1. What is the definition of convergence of a sequence?

The convergence of a sequence refers to the idea that as the terms of a sequence get closer and closer to a certain value, called the limit, the sequence can be said to converge towards that limit. In other words, as the sequence progresses, its terms will approach and eventually reach a specific value.

2. How do you prove that a sequence is convergent?

A sequence can be proven to be convergent by showing that the terms of the sequence get arbitrarily close to the limit as the sequence progresses. This can be done through various methods, such as using the definition of convergence, the limit comparison test, or the Cauchy criterion.

3. Can a sequence have multiple limits?

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

4. What is the difference between absolute and conditional convergence of a sequence?

Absolute convergence refers to a sequence where the sum of the absolute values of the terms converges, while conditional convergence refers to a sequence where the sum of the terms converges, but the sum of the absolute values of the terms does not converge.

5. What is the relationship between convergence and divergence of a sequence?

Convergence and divergence are two opposite concepts when it comes to sequences. A sequence is considered to be convergent if its terms approach a specific limit, while a sequence is considered to be divergent if its terms do not approach a specific limit. In other words, a convergent sequence has a finite limit, while a divergent sequence does not have a limit or the limit is infinite.

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