grandes-ecoles 2018 Q35

grandes-ecoles · France · centrale-maths2__official Taylor series Prove smoothness or power series expandability of a function

Show an analogous result to $|f(0)| \leqslant \sup_{t \in \mathbb{R}} |f(r\cos(t), r\sin(t))|$ for harmonic functions.

Show an analogous result to $|f(0)| \leqslant \sup_{t \in \mathbb{R}} |f(r\cos(t), r\sin(t))|$ for harmonic functions.