- #1
mcastillo356
Gold Member
- 589
- 312
- Homework Statement
- I've got a piecewise function, and wanted to demonstrate its continuity using sequences
- Relevant Equations
- ##f(x)=\begin{cases}{\left|{x}\right|}&\text{if}&x\in\mathbb{Q}\\0&\text{if}&x\not\in\mathbb{Q}\end{cases}##
I've been given the proof, but don't understand; to calculate the limit of ##f## when ##x## tends to zero it's enough to see that if ##\{x_n\}_{n=1}^\infty## is a sequence that tends to ##0##, then $$f(x_n)=\begin{cases}{\left|{x_n}\right|}&\text{if}&x\in\mathbb{Q}\\0&\text{if}&x_n\not\in\mathbb{Q}\end{cases}$$ clearly tends to ##0##. Hence, ##\lim_{x\to 0}f(x)=0##
Question: why ##f(x_n)## tends clearly to zero?. I know I've already answered it on this post, but I don't understand.
PS: If the place I've published is the wrong one, please move it.
Question: why ##f(x_n)## tends clearly to zero?. I know I've already answered it on this post, but I don't understand.
PS: If the place I've published is the wrong one, please move it.