Discontinuous function proof using $\epsilon - \delta$
69066
$\epsilon{\rm -}\delta$ proof of the discontinuity of Dirichlet's function
52388
The equivalence of open-set definition of continuous mappings to the $\epsilon-\delta$ definition
4656
Prove that there is a $\delta$ such that $\int_{0}^{1} (f(x))^2dx\leq \delta$$\int_{0}^{1} (f'(x))^2dx$ for all $f$ with these conditions
11167
A counterexample of a differentiable function on an interval whose derivative is discontinuous
88240
Two functions discontinuous, but sum continuous
42084
Set of points of continuity are $G_{\delta}$
118138
$\epsilon - \delta$ proof that $\lim_{x \to a} \sqrt x = \sqrt a$
7358
For each $y \in \mathbb{R}$ either no $x$ with $f(x) = y$ or two such values of $x$. Show that $f$ is discontinuous.
29276
technique of proving continuity complex function
74793
The primitive of a discontinuous function?
38886
Discontinuous function on Q
10749
Proving $\lim_{x\to 1} x^3=1$ with $\epsilon$-$\delta$ definition
22210
Points of discontinuity of a bijective function $f:\mathbb{R} \to [0,\infty)$
132873
Understanding Epsilon-Delta Proof
20688
Discontinuous functions with closed graphs
125754
Proving or disproving a statement about continuity and limits
82659
How to write $\delta (f(x))$ in terms of $\delta (x)$?