Question
Question: A focal chord of the parabola y<sup>2</sup> = 4ax makes an angle π/3 with the axis of the parabola, ...
A focal chord of the parabola y2 = 4ax makes an angle π/3 with the axis of the parabola, Then the length of the focal chord is
A
4a/3
B
8a/3
C
2a/3
D
16a/3
Answer
16a/3
Explanation
Solution
If a focal chord of a parabola makes an angle ‘θ’ with x-axis; then the length of the focal chord is 4a cosec2θ. Given θ = π/3.
∴ Length of focal chord = 4a. cosec2 π/3 = 316a