Question 1
Which statement is the $\varepsilon$-$\delta$ definition of continuity of $f$ at $a$?
Question 2
Which statement is equivalent to saying that $f$ is not continuous at $a$?
Question 3
Which condition matches the sequential characterization of continuity of $f$ at $a$?
Question 4
For $f(x)=3x+1$, which choice of $\delta$ works to prove continuity at any point $a$ for a given $\varepsilon>0$?
Question 5
For $f(x)=x^2$, a valid choice of $\delta$ to prove continuity at $a=2$ is:
