are polynomials infinitely many times differentiable?

We can take as many non-zero derivatives as the highest power of the polynomial dictates.

For example....

y = x^2

y' = 2x

y'' = 2

And the third derivative would be  0.

It's a matter of definition.

Do you think that zero is infinitely many times differentiable ?

But that doesn't answer the question.

This answers the question clearly, unless you have CDD. In fact, CPhill’s answer is oriented to the first anon’s un-exposited answer, so you have to be a m***n with CDD to think otherwise.

What do you want, a parchment signed by God-Almighty saying this question is answered?

Yes. A parchment signed by God-Almighty just might do.

This is an electronic parchment affirming the question is answered.

Quit pestering me with your petty problems.

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