Why do we need an open set to define differentiability?
41557
Most general $A \subseteq \mathbb R$ to define derivative of $f: A \to \mathbb R$?
151575
Differentiable bijection $f:\mathbb{R} \to \mathbb{R}$ with nonzero derivative whose inverse is not differentiable
115635
Differentiability of antiderivative and continuity of derivative
150833
Discontinuities of the derivative of a differentiable function on closed interval
70264
Prove that the inverse image of an open set is open
35671
Why can a discontinuous function not be differentiable?
85623
Proof of continuity implied by differentiability
56429
Extension of partial derivatives and the definition of $C^k(\overline{\Omega})$
43626
Open Mapping Theorem: counterexample
97735
Continuous functions are differentiable on a measurable set?
127964
Confused about the possibility of different differentiable structures.
93986
Connectivity, Path Connectivity and Differentiability
50506
What concept does an open set axiomatise?
27888
Why is $|x|$ not differentiable at $x=0$?
150005
Existence of points in a differentiable function
122003
From the limit definition of differentiability, determine where the function $f(x) = \sqrt{x}$ is differentiable?
131357
Prove that $f(x,y)=xy$ is differentiable using the definition