Sequences & Limits: Finding the Limit as n->inf

In summary, the given sequence, x_n(t), has a dependence on t in the interval [0, (1/n)] and [(1/n),1]. As n approaches infinity, the values of the sequence will range between 0 and 1. However, for a fixed x0 in [0,1], the limit of x_n(x0) as n approaches infinity is 0. This can be seen by choosing any t0 or x0 and observing that the function will merge to 0 as n approaches infinity.
  • #1
Somefantastik
230
0

Homework Statement



[tex] x_{n}(t) \left\{\begin{array}{cc}nt,&\mbox{ if }
0\leq t \leq \frac{1}{n}\\ \frac{1}{nt} & \mbox{ if } \frac{1}{n}\leq t \leq 1 \end{array}\right. [/tex]


Homework Equations





The Attempt at a Solution



Can someone help me get started finding the limit as n -> inf? I've never taken the limit of a sequence that has such a dependence on t.

For t in [0, (1/n)], the values of the sequence will range between 0 and 1, and for t in [(1/n),1], the values will range between 0 and 1 as well. It doesn't really matter how large you take n...
 
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  • #2
Pick a fixed x0 in [0,1] and think about limit x_n(x0) as n->infinity. If x0 is not zero there is always an N>0 such that 1/N<x0. That means for all n>N the definition of x_n(x0) is 1/(n*x0). What's the limit at x0?
 
  • #3
What do you mean by pick and x0? You mean, pick a t0?
 
  • #4
Somefantastik said:
What do you mean by pick and x0? You mean, pick a t0?

t0, x0 whatever. Sure, call the point t0 if you want.
 
  • #5
How about Alfred? Anyway, I think I got what you are saying. No matter what your choice for t, this function will merge to 0 as n -> inf.

thank you for your time.
 

1. What is a sequence in mathematics?

A sequence is a list of numbers arranged in a specific order. The numbers in a sequence follow a pattern or a rule.

2. What is a limit of a sequence?

The limit of a sequence is the value that the terms of the sequence approach as the sequence continues indefinitely. It can be thought of as the "end behavior" of the sequence.

3. How do you find the limit of a sequence?

To find the limit of a sequence, you can either use algebraic techniques such as factoring or simplification, or you can use graphical methods such as plotting the points on a graph to see the trend and estimate the limit.

4. What does it mean for a sequence to have a finite limit?

If a sequence has a finite limit, it means that the terms of the sequence eventually get closer and closer to a single, fixed value as the sequence continues. In other words, the values of the terms do not "blow up" or become infinitely large.

5. Why is finding the limit of a sequence important in mathematics?

Finding the limit of a sequence is important in mathematics because it helps us understand the behavior of a sequence as it approaches infinity. This concept is used in various areas of mathematics, such as calculus, where it is crucial in determining the behavior of functions and solving real-world problems.

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