Freshman intended math+cs major.
Welcome to discuss 104 problems or other math/cs with me ^^ happy to learn from everyone!!
Courses I have taken:
math W128A
math 53
math 54
cs 61A
Current Course:
math 104
math 113
math 110
cs 70

Peano axiom for $\mathbb{N}$ produce axiomic instead of constructive definition, but how can we know that the $\mathbb{N}$ that satisfies all the axioms is unique?
Is it that we use these axioms to define a group of sets that can be considered “natural numbers”, and then use induction to show that A and B that satisfies all axioms must be equal? (since we already have inductive property for both A and B now)
I finally understood how to upload Ross 3.2 to this site now..

Real number has two defs, but textbook did not show the equivalence and their equivalence to completeness… HW is here

HW for sequence and limits I did not finish 10.11 I found an inf for the sequence to be 1/2 but I can no longer proceed further…

Got a hint from a textbook to evaluate $\int_0^{\frac{\pi}{2}}\sin^{2n+1}x dx$ first, now it worked but literally dont understand how we are supposed to think about this at the first place :(

Subsequential limits are difficult for me.

During class there are 2 that I did not follow at first:

1: there is a subsequence approaching $limsup(s_n)$ monotonically.

2: the set of subsequential limit of a bounded sequence is closed (This one is better explained just by a graph)

Ross 3.2 is quite easy this week though, but cantor diagonal is a really amazing technique.