Express the improper integral as a limit$.$ Then evaluate the improper integral. If the integral is not convergent, answer "divergent."

${\displaystyle \underset{1}{\overset{}{}}}\frac{5}{x^3}dx$

Express the improper integral as a limit$.$ Then evaluate the improper integral. If the integral is not convergent, answer "divergent." Hint: An integral table may be useful.

${\displaystyle \underset{0}{\overset{}{}}}\frac{1}{4+x^2}dx$