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Emil Jeřábek
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If f is infinitely differentiable then f coincides with a polynomial

Let $f$ be an infinitely differentiable function on $[0,1]$ and suppose for each $x \in [0,1]$ there is an integer $n \in \mathbb{N}$ such that $f^{(n)}(x)=0$. Then does $f$ coincide on $[0,1]$ with some polynomial? If yes then how.

I thought of using Weierstrass approximation theorem, but couldn't succeed.

C.S.
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