Q28 of 63 Page 202

Find the equation of each of the following parabolas

Vertex at (0, 4), focus at (0, 2)

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


the distance between the vertex and directrix is same as the distance between the vertex and focus.


Directrix is y – 6 = 0


For any point of P(x, y) on the parabola


Distance of P from directrix = Distance of P from focus


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


Distance between the point of intersection & centre = [Distance Formula] {Between (x,y) & (0,2)}




Squaring both the sides,


x2 + y2 - 4y + 4 = (y – 6)2


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


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


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