7 In this question you must show detailed reasoning.
A curve has equation \(y = 4 x ^ { 3 } - 6 x ^ { 2 } - 9 x + 4\).
- Sketch the gradient function for this curve, clearly indicating the points where the gradient is zero.
- Find the set of values of \(x\) for which the gradient function is decreasing. Give your answer using set notation.