(i) Differentiate \(y = 2x + \frac{8}{x^2}\) with respect to \(x\):
\(\frac{dy}{dx} = 2 - \frac{16}{x^3}\).
Differentiate again to find \(\frac{d^2y}{dx^2}\):
\(\frac{d^2y}{dx^2} = \frac{48}{x^4}\).
(ii) Set \(\frac{dy}{dx} = 0\) to find the stationary point:
\(2 - \frac{16}{x^3} = 0 \Rightarrow x = 2\).
Substitute \(x = 2\) into the original equation:
\(y = 2(2) + \frac{8}{2^2} = 4 + 2 = 6\).
Stationary point is \((2, 6)\).
Since \(\frac{d^2y}{dx^2}\) is positive, the stationary point is a minimum.
(iii) At \(x = -2\), \(\frac{dy}{dx} = 4\), so the gradient of the tangent is 4.
The gradient of the normal is \(-\frac{1}{4}\).
Equation of the normal: \(y + 2 = -\frac{1}{4}(x + 2)\).
Set \(y = 0\) to find the x-intercept:
\(0 + 2 = -\frac{1}{4}(x + 2) \Rightarrow x = -10\).
The normal intersects the x-axis at \((-10, 0)\).