Use Root Test to determine whether the series is convergent $($absolute$)$ or divergent.

$($a$){\displaystyle \underset{n=1}{\overset{}{}}}(\frac{2n^2+1}{3n^2+5}{)}^n$

$($b$){\displaystyle \underset{n=1}{\overset{}{}}}\frac{(-2{)}^n}{n^n}$