(a)
\The function
and the interval is
.
Find critical points.
\Differentiate on each side with respect to
.


The critical points exist when
.
Equate
to zero.

Therefore critical points are
.
The test intervals are
,
and
.
| Interval | \Test Value | \ \
Sign of | \
Conclusion | \
![]() | \
![]() | \
\
| \
Decreasing | \
![]() | \
![]() | \
\
| \
Increasing | \
![]() | \
![]() | \
\
| \
Decreasing | \
![]() | \
![]() | \
\
| \
Increasing | \
![]() | \
![]() | \
\
| \
Decreasing | \
![]() | \
![]() | \
\
| \
Increasing | \
![]() | \
![]() | \
\
| \
Decreasing | \
![]() | \
![]() | \
\
| \
Increasing | \
The function is increasing on the intervals
,
,
, and
.
The function is decreasing on the intervals
,
,
and
.
(b)
\The function
and the interval is
.
From the first derivative test the function
changing from positive to negative at
.

Relative maximum point is
.
Similarly
has relative maximums at
and
.
From the first derivative test the function
changing from negative to positive at
.

Relative minimum point is
.
Similarly
has relative minimums at
,
and
.
(c)
\Graph :
\The graph of the function
is

(a)
\The function is increasing on the intervals
,
,
, and
.
The function is decreasing on the intervals
,
,
and
.
(b)
\Relative maximum point is
,
and
.
Relative minimum point is
,
,
and
.
(c)
\The graph of the function
is:
.