If the vertex of a parabola is (2,-1) and the equation of its directrix is 4x-3y=21, then …

Question

If the vertex of a parabola is $(2,-1)$ and the equation of its directrix is $4x-3y=21$, then the length of its latus rectum is:

Accepted Answer

Vertex of Parabola : (2, -1)

and directrix : 4x - 3y = 21

Distance of vertex from the directrix

$$a = \left| {{{8 + 3 - 21} \over {\sqrt {25} }}} \right| = 2$$

$$\therefore$$ length of latus rectum = 4a = 8

Solutions · 1