(a) A curve C is defined by the equation xy + y² – x³ = 7.
Find the coordinates of the point where the tangent line to the curve C is parallel to the y-axis and state the equation of this tangent line.
(b) A curve is defined parametrically by the equations 
.
The fixed point P on the curve has parameter p. Find the equation of the normal to the cure at the point P, leaving your answer in terms of a and p.
Given that the normal at point P does not meet the curve again, find exactly the range of values of p.
