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math104-s22:s:jiayinlin:start [2022/02/12 21:51] jiayin_lin [Feb 11th] |
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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. | ||
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| + | Metric space is really hard, even at the beginning. Here is my [[HW 5]], I spent a lot of time on Ross 13.17. | ||
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| + | 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. | ||
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| + | ====Mar 9th==== | ||
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| + | I have done [[HW 6]] but the last question I do not get it. | ||
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| + | 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). | ||
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| + | ====Mar 10th==== | ||
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| + | [[hw7]] was easy, but the first question I think there must be better ways for it. Mine was literally all over the place... | ||
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| + | 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, | ||
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| + | ====Mar 18th==== | ||
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| + | [[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. | ||
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| + | ====Apr 9th==== | ||
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| + | I did horribly in MT2, so I have to study harder. [[HW9]] is here. | ||
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| + | I did the first question wrong, but I figured out that integrate my answer will work. This one was really cool. | ||
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| + | {{: | ||
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| + | This was my original answer I thought I was constructing some that vanish at both points | ||
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| + | {{: | ||
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| + | This works now properly | ||
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| + | ====Apr 17th==== | ||
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| + | I had a really hard time going through R-S integral. I missed a class and I cannot follow anymore... :( | ||
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| + | I have been frantically going through Ross 35 but I found there are so many material. | ||
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| + | I did [[hw10]] with no ease, and I hope they are correct. | ||
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| + | ====Apr 25th==== | ||
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| + | 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. | ||