Q18 of 63 Page 202

If the points (0, 4) and (0, 2) are respectively the vertex and focus of a parabola, then find the equation of the parabola.

Vertex = (0,4) Focus = (0,2)


So, the directrix of the parabola is y = 6,


Since, Distance of (x, y) from (0, 2) and perpendicular distance from (x, y) to directrix are always equal.


Using Distance Formula & Perpendicular Distance Formula,


Perpendicular Distance (Between a point and line) = , whereas the point is and the line is expressed as ax + by + c = 0 i.e.., PM x(0) + y – 6 = 0 & (x, y)


Distance between the point of intersection & centre = [Distance Formula]



Squaring both the sides,



x2 + y2 - 4y + 4 = y2 - 12y + 36


x2 + 8y – 32 = 0


Hence, the required equation is x2 + 8y – 32 = 0.


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