Question
Question: The polars at (1, 7), (4, 8) w.r.t. y<sup>2</sup> = 4x meet at C. Then the equation of the polar of ...
The polars at (1, 7), (4, 8) w.r.t. y2 = 4x meet at C. Then the equation of the polar of C w.r.t. the parabola is
A
x + y - 8 = 0
B
x + y - 12 = 0
C
x - 3y + 20 = 0
D
x-y + 20 = 0
Answer
x - 3y + 20 = 0
Explanation
Solution
Polars of collinear points are concurrent.
∴ The polar of ‘C’ is the line joining the points (1, 7) and
(4, 8) ie., x- 3y+20 = 0.