Questions:
  - From the lecture on April 15th
    - {{math104-s21:s:pasted:20210422-091401.png}}
    * I cannot think of why $x^2$ is an example of f(x) ≠ P_x0(x)
    * I tried fixing $x_0 = 0$, so $P_0(x) = ∑ c_n \cdot (x)^n$, where $\alpha = lim sup |c_n|^{1/n} = 1$, so $R=1$ 
    * Then $f(0.5) = 0.25 = P_0(0.5) = 0 + 0 + 1 * 0.5 ^ 2 + 0 + ... + 0$
  - A question from my friend, finding open cover
    - {{math104-s21:s:pasted:20210506-085558.png}}
    - My attempt:
    * {{math104-s21:s:pasted:20210506-091704.png}}