Equicontinuous sequences of functions vs. continuous functions

In summary, the conversation involves discussing a problem and solution written in Latex. The first part needs verification and the second part requires guidance. The speaker suggests removing the subscript k from the notation for delta and using delta_n instead.
  • #1
jdinatale
155
0
Hello,

below I have the problem and solution typed in Latex. For the first part, I just want someone to verify if I am correct.

For the second part, I need guidance in the right direction

math1.png

 
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  • #2
I think you've got the right idea for a), but your description is a little muddled. Like what is the k subscript on your delta supposed to mean? For b) think about how you would go about choosing a delta to satisfy [itex]|g_n(1)-g_n(x)|<\frac{1}{2}[/itex].
 
  • #3
Dick said:
I think you've got the right idea for a), but your description is a little muddled. Like what is the k subscript on your delta supposed to mean? For b) think about how you would go about choosing a delta to satisfy [itex]|g_n(1)-g_n(x)|<\frac{1}{2}[/itex].

Thank you. The k on the delta is just to show that for a given f_n and epsilon, you will get a particular delta which I call delta subscript k. I guess I could remove that.
 
  • #4
jdinatale said:
Thank you. The k on the delta is just to show that for a given f_n and epsilon, you will get a particular delta which I call delta subscript k. I guess I could remove that.

Wouldn't it make more sense that if delta depends on f_n, that that particular delta should be labeled delta_n, instead of the meaningless subscript k? That's what I'm talking about with notation.
 

What is the difference between equicontinuous sequences of functions and continuous functions?

Equicontinuous sequences of functions are a sequence of functions that are uniformly continuous, meaning that for any given epsilon, there exists a delta such that for all points in the domain, the difference in function values is less than epsilon. Continuous functions, on the other hand, are functions that have no abrupt changes or breaks in their graph, and can be drawn without lifting the pencil.

Why is equicontinuity important in the study of functions?

Equicontinuity is important because it allows us to make important conclusions about the behavior of a sequence of functions, even if we only know the behavior of individual functions in the sequence. It also helps us to prove the convergence of sequences of functions, which is important in many areas of mathematics and science.

What are some examples of equicontinuous sequences of functions?

An example of an equicontinuous sequence of functions is the sequence of polynomials f_n(x) = 1/n * x^2, where n is a positive integer. Each function in the sequence is uniformly continuous, and the sequence converges to the zero function, which is also uniformly continuous.

Can a sequence of continuous functions be equicontinuous?

Yes, a sequence of continuous functions can also be equicontinuous. This is because continuity is a necessary condition for equicontinuity, but not a sufficient one. A sequence of continuous functions that are also uniformly continuous will be equicontinuous.

What is the relationship between uniform continuity and equicontinuity?

Uniform continuity is a stronger condition than equicontinuity. All uniformly continuous functions are also equicontinuous, but not all equicontinuous functions are uniformly continuous. In other words, uniform continuity is a subset of equicontinuity.

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