7.
$$f ( x ) = x ^ { 3 } - 9 x ^ { 2 }$$
- Find \(\mathrm { f } ^ { \prime } ( x )\).
- Find \(\mathrm { f } ^ { \prime \prime } ( x )\).
- Find the coordinates of the stationary points of the curve \(y = \mathrm { f } ( x )\).
- Determine whether each stationary point is a maximum or a minimum point.