Function differentiable at one point and nowhere else continuous.

966 Views Asked by At

Is it possible to construct such a function? Just wondering.

Specifically, I am thinking of $f:\mathbb{R}\to\mathbb{R}$ such that $f'(0)$ exists and $f$ is discontinuous for all $x\in\mathbb{R}-\{0\}$.

1

There are 1 best solutions below

0
On BEST ANSWER

Consider

$$ f(x) = \left\{ \begin{array}{lr} x^2 & : x \in \mathbb{Q}\\ 0 & : x \notin \mathbb{Q} \end{array} \right. $$