The function is
.
Observe the graph :
\The function
is increasing on the interval
and 
Thefunction
is decreasing on the interval 
Find open interval analytically.
\
Apply derivative to find the critical numbers.
\
Equate it to zero .
\
The critical points are
and
.
Test intervals are
,
and
.
| Test intervals | \Test value | \sign of ![]() | \
conclusion | \
![]() | \
![]() | \
![]() | \
Increasing | \
![]() | \
![]() | \
![]() | \
Decreasing | \
![]() | \
![]() | \
![]() | \
Increasing | \
The function
is increasing on the intervals
and 
Thefunction
is decreasing on the interval 
The function
is increasing on the intervals
and 
Thefunction
is decreasing on the interval 