Convergence of Sequences in [0,1]

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SUMMARY

The discussion centers on the convergence of three sequences defined on the interval [0,1]: (i) \( s_n(x) = n^2x^2(1 - \cos(\frac{1}{nx})) \), (ii) \( s_n(x) = \frac{nx}{x+n} \), and (iii) \( s_n(x) = n\sin(\frac{x}{n}) \). The conclusions reached are that sequence (i) converges pointwise but not uniformly, while sequences (ii) and (iii) converge both pointwise and uniformly to their respective limits. The participants emphasize the importance of differentiability and bounded derivatives in establishing uniform convergence.

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  • #31
Dick said:
Well, yes. Just interchanging the order just interchanges increasing/decreasing and signs. It doesn't make any real difference to the problem. But ##|s_n(x) - s(x)|## is still increasing as a function of x on [0,1]. Not decreasing. It's an absolute value. I'm still not sure you are clear on what's important and what is not.

Oh so It doesn't make any difference at all. I see now.

It's just |a-b| = |b-a| looked wrong to me for a moment ( Can't even explain why). Now that that's clear I think I'm good.
 
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  • #32
Zondrina said:
Oh so It doesn't make any difference at all. I see now.

It's just |a-b| = |b-a| looked wrong to me for a moment ( Can't even explain why). Now that that's clear I think I'm good.

That is great!
 

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