The function is .
Find the critical numbers by applying derivative .
\Equate it to zero .
\Therefore the critical numbers are and
.
Test intervals are ,
and
.
Test intervals | \ \
Test value \ | \
\
Sign of | \
Conclusion | \
![]() | \
![]() | \
\
| \
Decreasing | \
![]() | \
![]() | \
\
| \
Increasing | \
![]() | \
![]() | \
\
| \
Decreasing | \
So the function is decreasing on the intervals
and
.
The function is increasing on the interval
.
The function is decreasing on the intervals
and
.
The function is increasing on the interval
.