If 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
(A)2
(B)8✓ Correct
(C)12
(D)16
Answer: (B)
Solution
The distance from the vertex (2,−1) to the directrix 4x−3y=21 is a=16+9∣4(2)−3(−1)−21∣=5∣8+3−21∣=510=2. The length of the latus rectum is 4a=4(2)=8.
JEE Main · 2022 · 28 Jun 2022 · Shift 2 · Single correct option