(a)
\Increasing test :
\If on the interval, then
is increasing on the interval.
Observe the graph.
\ on the interval
and
then
is increasing on the interval
and
.
(b)
\First derivative test :
\\
Consider is a critical number of a continuous function
.
(i) If changes from positive to negative at
, then
has a local maximum at
.
(ii) If changes from negative to positive at
, then
has a local minimum at
.
(iii) If does not change sign at
, then
has no local maximum or minimum at
.
Observe the graph.
\ has a local maximum at
, because
changes its sign from positive to negative.
has a local minimum at
and
because
changes its sign from negative to positive.
(c)
\Concave upward :
\The function is concave up when
is increasing in the interval.
The function is concave upward over the interval
,
and
.
Concave downward :
\The function is concave down when
is decreasing in the interval.
Observe the graph.
\The function is concave downward over the interval
,
and
.
(d)
\Point of inflection :
\If the graph is of the first derivative then the local minimum or maximum will be the inflection points, since the inflection points occurs where the second derivative will be zero.
\The derivative of the function has local maximum at .
The derivative of the function has local minimum at .
The point of inflection occur at and
.
(a) is increasing on the interval
and
.
(b) has a local maximum at
and local minimum at
and
.
(c) is concave upward over the interval
,
and
.
is concave downward over the interval
,
and
.
(d) has inflection points at
and
.