Why isn't this function differentiable?
43874
Differentiability implies continuity - A question about the proof
2506
twice differentiable functions
148737
Is $|xy|$ differentiable in $(0,0)$?
146888
Derivative of function with 2 variables
127114
Differentiability implying continuity
142870
Prove the function is not differentiable at (0,0)
147758
Differentiable but not continuously differentiable.
135199
Looking for a function $f$ that is $n$-differentiable, but $f^{(n)}$ is not continuous
19828
Show that $\frac{x^3}{x^2+y^2}$ is not differentiable at $(0,0)$, even though all directional derivatives exist
18825
Integrable but not differentiable function
108126
Scoping in assigning a derivative
102549
Check the differentiability of the given function.
143593
A sequence of differentiable functions that converge uniformly to a non differentiable function - is my example correct?
122003
From the limit definition of differentiability, determine where the function $f(x) = \sqrt{x}$ is differentiable?
90780
Why does implicit differentiation work on non-functions?
62581
What is an example that a function is differentiable but derivative is not Riemann integrable
112859
$f(x,y) = \frac{x^3y}{x^4 + y^2}$ is not differentiable at $(0,0)$.