Answer
(a) A series $\Sigma{a_n}$ is an absolutely convergent if $\Sigma|{a_n}|$ converges.
Here, $\Sigma|{a_n}|$ means the sum of the absolute value of the terms.
(b) Such series converges since if $\Sigma|{a_n}|$ converges, then $\Sigma|{a_n}|$ also converges.
(c) A series $\Sigma{a_n}$ is a conditionally convergent series if $\Sigma|{a_n}|$ diverges but itself converges.
Here, $\Sigma|{a_n}|$ means the sum of the absolute value of the terms.
Work Step by Step
(a) A series $\Sigma{a_n}$ is an absolutely convergent if $\Sigma|{a_n}|$ converges.
Here, $\Sigma|{a_n}|$ means the sum of the absolute value of the terms.
(b) Such series converges since if $\Sigma|{a_n}|$ converges, then $\Sigma|{a_n}|$ also converges.
(c) A series $\Sigma{a_n}$ is a conditionally convergent series if $\Sigma|{a_n}|$ diverges but itself converges.
Here, $\Sigma|{a_n}|$ means the sum of the absolute value of the terms.