grandes-ecoles 2010 QI.A.3

grandes-ecoles · France · centrale-maths1__pc Taylor series Formal power series manipulation (Cauchy product, algebraic identities)
For every integer $n \in \mathbb{N}$, we set $F_n(x) = \cos(n \arccos x)$.
Deduce from the above that $F_n$ extends to $\mathbb{R}$ as a unique polynomial function, whose degree and leading coefficient should be specified.
For every integer $n \in \mathbb{N}$, we set $F_n(x) = \cos(n \arccos x)$.

Deduce from the above that $F_n$ extends to $\mathbb{R}$ as a unique polynomial function, whose degree and leading coefficient should be specified.