Consider
and
.
Direct comparision test :
\If
for all
.
1. If
converges, then
converges.
2. If
diverges, then
diverges.
By comparision test, prove that
.
Find the value of
so that
.
Consider function
.
, when
.
for
.
Therefore,
,
.
for
.
for
.
Therefore,
.
Consider
.
The series
is converges by
-series test.
Since
is converges, by comparision test
is converges.
The statement is proved.