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math104-s22:s:jiayinlin:start [2022/02/12 21:51]
jiayin_lin [Feb 11th]
math104-s22:s:jiayinlin:start [2026/02/21 14:41] (current)
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 When we want to analyze the set of subsequential limits, it there anything else than limsup and liminf that we can do...?  When we want to analyze the set of subsequential limits, it there anything else than limsup and liminf that we can do...? 
  
 +if we can show that a sequence is bounded by the max of two sequences that has divergent series, can we say the series diverges? (something like comparison test)
  
 +====Feb 25th====
  
 +MT went smooth although I made stupid mistakes.
 +
 +Metric space is really hard, even at the beginning. Here is my [[HW 5]], I spent a lot of time on Ross 13.17.
 +
 +It is really smart that someone reminded me of taking a Q inside each interval, since they are disjoint they are all unique, and thus there is a bijection.
 +
 +====Mar 9th====
 +
 +I have done [[HW 6]] but the last question I do not get it.
 +
 +I see that cantor set can be a valid counter example, but I still dont understand how the given statement is wrong. It seems a really valid bijection from every open interval to its left (infimum).
 +
 +====Mar 10th====
 +
 +[[hw7]] was easy, but the first question I think there must be better ways for it. Mine was literally all over the place...
 +
 +The question in class in interesting that every path-connected set is a connected set. I did not have time to get to that one during discussion, but my idea was that if the set $A$ is not connected, then $A=B \cup C$, B and C are clopen, nonempty and disjoint. Then take an element $x\in B$ and $y\in C$, if $f: [0,1]\to A$ satisfies $f(0)=x$ f is continuous, then $f^{-1}(B)$ is clopen and contains 0. However, we know [0,1] is connected, so the only nonempty clopen subset is itself, so $f([0,1])=B$, which means $f(1)\not=y$.
 +
 +====Mar 18th====
 +
 +[[hw 8]] is easy for me, but I dont quite get the Weierstrass-M test since for me I feel it is a too strong requirement that sup of all $|f_n|$ is bounded by something that sum up to converge then the the convergence is too obvious. I am concerned about what happens when $\sum\limits_m^n sup(|f(x)|)$ is not cauchy (you are adding up values for different x in each term) but $sup(\sum\limits_m^n |f(x)|)$ converge to 0 for all x and the series is still uniform cauchy and how we identify this sort.
 +
 +====Apr 9th====
 +
 +I did horribly in MT2, so I have to study harder. [[HW9]] is here.
 +
 +I did the first question wrong, but I figured out that integrate my answer will work. This one was really cool.
 +
 +{{:math104-s22:s:jiayinlin:pasted:20220415-164451.png}}
 +
 +This was my original answer I thought I was constructing some that vanish at both points
 +
 +{{:math104-s22:s:jiayinlin:pasted:20220415-164526.png}}
 +
 +This works now properly
 +
 +====Apr 17th====
 +
 +I had a really hard time going through R-S integral. I missed a class and I cannot follow anymore... :(
 +
 +I have been frantically going through Ross 35 but I found there are so many material.
 +
 +I did [[hw10]] with no ease, and I hope they are correct.
 +
 +====Apr 25th====
 +
 +This [[hw11]] is quite easy for me though the last one I took some time to come up with, because I am too far from being familiar with R-S integral.
math104-s22/s/jiayinlin/start.1644702703.txt.gz · Last modified: 2026/02/21 14:43 (external edit)