11. The curve \(C\) has equation
$$y = 2 x - 8 \sqrt { } x + 5 , \quad x \geqslant 0$$
- Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\), giving each term in its simplest form.
The point \(P\) on \(C\) has \(x\)-coordinate equal to \(\frac { 1 } { 4 }\)
- Find the equation of the tangent to \(C\) at the point \(P\), giving your answer in the form \(y = a x + b\), where \(a\) and \(b\) are constants.
The tangent to \(C\) at the point \(Q\) is parallel to the line with equation \(2 x - 3 y + 18 = 0\)
- Find the coordinates of \(Q\).