Question

If (4, 0) is the vertex and y-axis, the directrix of a parabola then its focus is

Solution

Correct option is

(8, 0)

 

If A(4, 0) is vertex of parabola, and y-axis is its directrix, SIS focus, then by def.

    OA = AS but OA = 4,   OS = OA + AS = 8

  S is (8, 0).

                                                                               

SIMILAR QUESTIONS

Q1

The equation of normal at the point  to the parabola y2 = 4ax, is

Q2

The equation of tangent at the point (1, 2) to the parabola y2 = 4ax, is

Q3

If a tangent of y2 = ax made angle of 450 with the x-axis, then its point of contact will be

Q4

If a normal drawn to the parabola y2 = 4ax at the point (a, 2a) meets parabola again on (at2, 2at), then the value of t will be

Q5

If the straight line x + y = 1 touches the parabola y2 – y + x = 0, then the coordinates of the point of contact are

Q6

The angle of intersection between the curves y2 = 4x and x2 = 32y at point (16, 8) is

Q7

The pole of the line lx + mx + n = 0 with respect to the parabola y2 = 4ax is

Q8

Two tangent are drawn from the point (–2, –1) to the parabola y2 = 4x. if  is the angle between them, then 

Q9

The conic represented by the equation  is

Q10

The straight line y = mx + c touches the parabola y2 = 4a(x + a) if