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math104-s21:s:kelvinlee [2021/05/11 10:39]
202.81.230.88 [Questions]
math104-s21:s:kelvinlee [2026/02/21 14:41] (current)
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 ===== Questions ===== ===== Questions =====
  
-1. What's the difference between ? \\+1. What's the difference between continuity and uniform continuity ? \\
 2. What's the difference between pointwise convergence and uniform convergence? \\ 2. What's the difference between pointwise convergence and uniform convergence? \\
 3. Is a series of continuous functions necessarily continuous? \\ 3. Is a series of continuous functions necessarily continuous? \\
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 \lim _{n \rightarrow \infty} \int_{a}^{b} f(x) \sin (n x) d x=0. \lim _{n \rightarrow \infty} \int_{a}^{b} f(x) \sin (n x) d x=0.
 $$ $$
-5. (Yuwei Fan's practice final) Suppose that $f:[1, \infty) \rightarrow \mathbb{R}$ is ]$. Prove that there exists $M>0$ such that $\frac{|f(x)|}{x} \leq M$ holds for any $x \geq 1$. \\+5. (Yuwei Fan's practice final) Suppose that $f:[1, \infty)$ $\rightarrow \mathbb{R}$ is \text{uniformly continuous} on $[1, \infty)$. Prove that there exists $M>0$ such that $\frac{|f(x)|}{x} \leq M$ holds for any $x \geq 1$. \\
 6. What are some nice properties that continuity preserves? \\ 6. What are some nice properties that continuity preserves? \\
 ** Answer: ** Compactness, connectedness. ** Answer: ** Compactness, connectedness.
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 37. A function $f: \mathbb{R} \rightarrow \mathbb{R}$ is said to satisfy the Lipshitz condition of order $\alpha$ at $a \in \mathbb{R}$ if there is a constant $M$ and a neighborhood of $a$ such that 37. A function $f: \mathbb{R} \rightarrow \mathbb{R}$ is said to satisfy the Lipshitz condition of order $\alpha$ at $a \in \mathbb{R}$ if there is a constant $M$ and a neighborhood of $a$ such that
 $$ $$
-|f(x)-f(a)|<M|x-a|^{\alpha}+\left|f(x)-f(a)\right|<M|x-a|^{\alpha}
 $$ $$
 Show that if $f$ has the Lipschitz condition of order $\alpha$ for $\alpha>0$, then $f$ is continuous. Give an example of a function $f$ which has Lipschitz condition of order 0 which is not continuous at $c$. \\ Show that if $f$ has the Lipschitz condition of order $\alpha$ for $\alpha>0$, then $f$ is continuous. Give an example of a function $f$ which has Lipschitz condition of order 0 which is not continuous at $c$. \\
math104-s21/s/kelvinlee.1620729599.txt.gz · Last modified: 2026/02/21 14:44 (external edit)