Graph the derivative function with the points:
\Graph :
\1. Draw the coordinate plane.
\2. Plot the points.
\3. Connect the points with a smooth curve.
\
Observe the derivative graph:
\Critical points are the points where the curve touches the
- axis.
The graph is increasing on
since
on
.
The graph is again decreasing on
since
on
.
Now draw the rough graph of .
(c)
\ changes from negative to positive at
.
Therefore according to first derivative test , the function has minimum at .
changes from positive to negative at
.
Therefore according to first derivative test , the function has maximum at .
(a)
\(b) Critical points are and
.
(c) has minimum at
.
has maximum at
.