5 The point \(P ( 2,1 )\) lies on the curve with equation
$$x ^ { 3 } - 2 y ^ { 3 } = 3 x y$$
Find
- the value of \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) at \(P\),
- the value of \(\frac { \mathrm { d } ^ { 2 } y } { \mathrm {~d} x ^ { 2 } }\) at \(P\).