(i) To find where the gradient is less than 5, first find the derivative: \(f'(x) = 3x^2 - 4x + 1\).
Set \(f'(x) < 5\):
\(3x^2 - 4x + 1 < 5\)
\(3x^2 - 4x - 4 < 0\)
Factorize: \((3x + 2)(x - 2) < 0\)
Find the critical points: \(x = -\frac{2}{3}\) and \(x = 2\).
The solution is \(-\frac{2}{3} < x < 2\).
(ii) To find stationary points, set \(f'(x) = 0\):
\(3x^2 - 4x + 1 = 0\)
Factorize: \((3x - 1)(x - 1) = 0\)
Solutions: \(x = \frac{1}{3}\) and \(x = 1\).
Find \(f(x)\) at these points:
\(f\left(\frac{1}{3}\right) = \left(\frac{1}{3}\right)^3 - 2\left(\frac{1}{3}\right)^2 + \frac{1}{3} = \frac{4}{27}\)
\(f(1) = 1^3 - 2 \times 1^2 + 1 = 0\)
Determine nature using second derivative: \(f''(x) = 6x - 4\).
\(f''\left(\frac{1}{3}\right) = 6\left(\frac{1}{3}\right) - 4 = -2\) (negative, so maximum)
\(f''(1) = 6 \times 1 - 4 = 2\) (positive, so minimum)
Maximum at \(\left( \frac{1}{3}, \frac{4}{27} \right)\); Minimum at \((1, 0)\).