Solution
= Solution
Termwise integration of the exponential <series> gives
$$
f_2(z)=2\sum_{n=0}^{\infty}\frac{(-1)^n}{n!(2n+1)}z^{-2n}.
$$
There are infinitely many negative Laurent coefficients, so zero is an <essential singularity>.
= Solution
Termwise integration of the exponential <series> gives
$$
f_2(z)=2\sum_{n=0}^{\infty}\frac{(-1)^n}{n!(2n+1)}z^{-2n}.
$$
There are infinitely many negative Laurent coefficients, so zero is an <essential singularity>.