(i) To find the coordinates of \(A\), set \(y = 0\) in the equation \(y = 4\sqrt{x} - x\):
\(4\sqrt{x} - x = 0\)
\(4\sqrt{x} = x\)
\(4 = \sqrt{x}\)
\(x = 16\)
Thus, \(A(16, 0)\).
To find the coordinates of \(M\), find the derivative \(\frac{dy}{dx} = 2x^{-\frac{1}{2}} - 1\) and set it to zero:
\(2x^{-\frac{1}{2}} - 1 = 0\)
\(2\sqrt{x} = 1\)
\(\sqrt{x} = \frac{1}{2}\)
\(x = 4\)
Substitute \(x = 4\) back into the original equation:
\(y = 4\sqrt{4} - 4 = 4\)
Thus, \(M(4, 4)\).
(ii) The volume \(V\) of the solid of revolution is given by:
\(V = \pi \int y^2 \, dx\)
\(V = \pi \int (4\sqrt{x} - x)^2 \, dx\)
\(V = \pi \int (16x + x^2 - 8x^{\frac{3}{2}}) \, dx\)
Integrate each term:
\(\pi \left[ 8x^2 + \frac{x^3}{3} - 8\frac{x^{\frac{5}{2}}}{\frac{5}{2}} \right]\)
Evaluate from 0 to 16:
\(V = \pi \left[ 8(16)^2 + \frac{(16)^3}{3} - 8\frac{(16)^{\frac{5}{2}}}{\frac{5}{2}} \right]\)
\(V = 136.5\pi\) (or \(137\pi\))