Thread: 3 times differentiable, but not 3 times continuously differentiable?

Does anyone know an example of a function that is 3 times differentiable, but not 3 times continuously differentiable?

Originally Posted by paupsers

Does anyone know an example of a function that is 3 times differentiable, but not 3 times continuously differentiable?

Try (with f(0) = 0). The third derivative will exist everywhere but be discontinuous at the origin.