Given:
$\displaystyle {A}_{{n}}={\frac{{{20}}}{{{2}^{{{n}}}}}}$
Determine:
(a) whether $\displaystyle {\sum_{{{n}={1}}}^{\infty}}{\left({A}_{{n}}\right)}$ is convergent. Preview Question 6 Part 1 of 2  
(b) whether $\displaystyle {\left\lbrace{A}_{{n}}\right\rbrace}$is convergent. Preview Question 6 Part 2 of 2  
If convergent, enter the limit of convergence. If not, enter "DNE" (unquoted).