Proving the non-differentiability of $|x| + x$.
106013
Given $f(x) = x + |x|$ for what values of $x$ is $f$ differentiable
35671
Why can a discontinuous function not be differentiable?
123602
Non integer derivative of $1/p(x)$
17928
How to prove the following expression does not depend on x?
83517
Taylor series of Infinitely differentiable function with nonnegative derivatives
154881
Question on differentiability of a continuous function
53497
Prove that the function is continuous and differentiable (not as easy as it sounds imo)
55268
Differentiable and Continuous functions on [0,1] with 'weird' conditions.
12726
Differentiating both sides of a non-differential equation
98462
Prove the inverse of a strictly increasing function is differentiable.
83915
Showing that a function is not differentiable
66951
Proving the existence of a sequence of functions converging to 0 with an added property
49408
Proof of the derivative of ln(x)
33130
$f$ differentiable except in $1$ point
150447
Prove a differentiable function between banach spaces is continuous
144023
Indefinite integral which is not differentiable
62352
Proving a scalar function is differentiable at the origin but that its partial derivatives are not continuous at that point.