Let $f : \Bbb R \to \Bbb R$ be a function . What can be said about the set of points where $f$ is not differentiable?
77624
Characterization of sets of differentiability
33130
$f$ differentiable except in $1$ point
145919
If $f: \Bbb{R}\rightarrow\Bbb{R}$ is continuous at $0$ and $f(x)=f(2x)$ for each $x\in\Bbb{R}$ then $f$ is constant.
102549
Check the differentiability of the given function.
18734
Showing that a function is differentiable
152877
Is a monotone differentiable function continuously differentiable?
109027
example of a non differentiable manifold
148737
Is $|xy|$ differentiable in $(0,0)$?
6417
Can a function be differentiable at the end points of its (closed interval) domain?
39057
Check the differentiablity of $\theta :\mathbb R^2 \setminus\{(0,0)\}\to \mathbb R$
22210
Points of discontinuity of a bijective function $f:\mathbb{R} \to [0,\infty)$
101281
Does there exist a smooth function which is nowhere analytic?
147758
Differentiable but not continuously differentiable.
144323
Differentiation of a function
135199
Looking for a function $f$ that is $n$-differentiable, but $f^{(n)}$ is not continuous
38417
How to find the non-differentiable point(s) of a given continuous function?
154881
Question on differentiability of a continuous function