Differentiability of polynomials
99984
Are polynomials infinitely many times differentiable?
61486
Show that $f$ is not differentiable at $(0,0)$ - $\frac{x_1^2x_2}{x_1^2+x_2^2}$
98462
Prove the inverse of a strictly increasing function is differentiable.
111458
Prove that $f$ is differentiable
55507
Multivariate differentiability verification
27265
Continuously differentiable map from $\mathbb{R}^{m+n}$ to $\mathbb{R}^n$
17440
Differentiation using first principles with rational powers
30533
Showing that this function is infinitely differentiable
8659
How do you show that $e^{-1/x^2}$ is differentiable at $0$?
136714
Proving that $\lim_{x \to 0} \frac{f(x)}{|x|}=1$ implies $f$ is not differentiable at $0$.
85480
Let $f(x,y)=\frac{x^3-y^3}{x^2+y^2}$. Is f differentiable in $(0,0)$?
129324
Let $f:[0;1]\to\mathbb R$ be continiously differentiable
97382
Continuous differentiability implies Lipschitz continuity
12726
Differentiating both sides of a non-differential equation
127114
Differentiability implying continuity
158681
How to show that $e^x$ is differentiable?
142870
Prove the function is not differentiable at (0,0)