Solution
= Solution
For every $z\in\mathbb C$,
$$
e^z=\sum_{n=0}^{\infty}\frac{z^n}{n!},\qquad
\sin z=\sum_{n=0}^{\infty}(-1)^n\frac{z^{2n+1}}{(2n+1)!}.
$$
= Solution
For every $z\in\mathbb C$,
$$
e^z=\sum_{n=0}^{\infty}\frac{z^n}{n!},\qquad
\sin z=\sum_{n=0}^{\infty}(-1)^n\frac{z^{2n+1}}{(2n+1)!}.
$$