Assignment:
The cross section of a parabolic reflector with 6-inch diameter is ground so that its vertex is 0.15 inch below the rim.
(a) Find the equation of the parabola after inserting an xy coordinate system with the vertex at the origin, the y axis (pointing upward) the axis of the parabola.
(b) How far is the focus from the vertex?
Provide complete and step by step solution for the question and show calculations and use formulas.