8 A curve has equation \(y = 2 x \cos 3 x + \left( 3 x ^ { 2 } - 4 \right) \sin 3 x\)
8
- Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\), giving your answer in the form \(\left( m x ^ { 2 } + n \right) \cos 3 x\), where \(m\) and \(n\) are integers.
[0pt]
[4 marks]
8 - Show that the \(x\)-coordinates of the points of inflection of the curve satisfy the equation
$$\cot 3 x = \frac { 9 x ^ { 2 } - 10 } { 6 x }$$
[4 marks]