Alternating Series Test :
\If the alternating series
satisfies
(i)
,
(ii)
, then the series is convergent.
The series is
.
Since the series is alternating, verify condition (i) and (ii) of the Alternating Series Test.
\It is not obvious that the sequence given by
is decreasing.
Consider the related function
.
Differentiate the function with respect to x .
\
If the function is decreasing, then
.
\


Thus,
is decreasing on the interval
.
This means that,
and therefore,
, when
.
The inequality
can be verified directly but all that really matters is that the sequence
is eventually decreasing.
Thus, condition (i) is verified.
\Find
.

As
, then
.

Evaluate the limits.
\
.
Thus, condition (ii) is verified.
\Thus the given series is convergent by the Alternating Series Test.
\The series
is convergent.