Question
Question: If a parabola touches both the co-ordinates axes then the equation of the directrix passing through ...
If a parabola touches both the co-ordinates axes then the equation of the directrix passing through (-1, 2) is
A
y+2x = 0
B
y – 2x = 0
C
x +2y = 0
D
x – 2y = 0
Answer
y+2x = 0
Explanation
Solution
Since the point of intersection of perpendicular tangents to a parabola lies on the directrix, the point of intersection (0, 0) of the coordinate axes is also lies on the directrix also given that directrix passes through (-1, 2).
∴ The equation directrix is y+2x = 0.