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.