Re: Help! Counterexample please!

In article
<d51ab19a-1bdd-4b2c-9fa3-3b5841414abe@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
hillaryr03@xxxxxxxxx wrote:

A function f differentiable at x = a implies that there exists å > 0
such that f is differentiable on (a - å, a + å ).

I know this is false, but I cannot come up with a counterexample. Help
please?

Define f(1/n) = 0, n = 1, 2, ..., f(x) = x^2 elsewhere. Take a =0.
.