Question

What does infinitely differentiable mean? What does infinitely differentiable mean? @Calculus1

Answer 1

that you can differentiate a function infinite number of times and the derivative is not eqal to 0 with all x(for example, sin(x)) and y=x is not infinitelly differentiable, because the second and higher derivatives are equal to 0

Answer 2

I read that all polynomials are infinitely differentiable. Is that true?