8.
$$f ( x ) = 2 - x + 3 x ^ { \frac { 2 } { 3 } } , \quad x > 0 .$$
- Find \(f ^ { \prime } ( x )\) and \(f ^ { \prime \prime } ( x )\).
- Find the coordinates of the turning point of the curve \(y = \mathrm { f } ( x )\).
- Determine whether the turning point is a maximum or minimum point.