constructing an infinitely differentiable function
32736
How to build a smooth "transition function" explicitly?
94944
Differentiable functions satisfying $f'(f(x))=f(f'(x))$
35671
Why can a discontinuous function not be differentiable?
6417
Can a function be differentiable at the end points of its (closed interval) domain?
28425
Constructing a sequence of function
108997
Continuous functions that attain local extrema at every point
34136
$f$ is differentiable in $[0,1]$ ,$\sup_{x\in[0,1]}|f'(x)| \le M\lt+\infty $
151575
Differentiable bijection $f:\mathbb{R} \to \mathbb{R}$ with nonzero derivative whose inverse is not differentiable
85157
Does a smooth "transition function" with bounded derivatives exist?
26955
Continuous at exactly two points and differentiable at exactly one of them
82210
Analytic continuation of function continuous on boundary
135199
Looking for a function $f$ that is $n$-differentiable, but $f^{(n)}$ is not continuous
147758
Differentiable but not continuously differentiable.
152877
Is a monotone differentiable function continuously differentiable?
111470
Proof of differentiability of $f(x)$
16375
Is the function differentiable at $0$?
72115
Why isn't there a continuously differentiable surjection from $I \to I \times I$?