Medium MCQ +4 / -1 PYQ · JEE Mains 2020

If one end of a focal chord AB of the parabola y2 = 8x is at $A\left( {{1 \over 2}, - 2} \right)$, then the equation of the tangent to it at B is :

  1. A 2x – y – 24 = 0
  2. B x – 2y + 8 = 0 Correct answer
  3. C x + 2y + 8 = 0
  4. D 2x + y – 24 = 0

Solution

Given parabola y<sup>2</sup> = 8x <br><br> $\therefore$ a = 2 <br><br>Let one end of focal chord is A(at<sup>2</sup> , 2at) = $\left( {{1 \over 2}, - 2} \right)$ <br><br>$\therefore$ 2at = -2 <br><br>$\Rightarrow$ t = $- {1 \over 2}$ <br><br>Other end of focal chord will be B$\left( {{a \over {{t^2}}}, - {{2a} \over t}} \right)$ $\equiv$ (8, 8) <br><br>$\therefore$ Equation of tangent at B is <br><br>8y = 4(x + 8) <br><br>$\Rightarrow$ x – 2y + 8 = 0

About this question

Subject: Mathematics · Chapter: Conic Sections · Topic: Parabola

This question is part of PrepWiser's free JEE Main question bank. 146 more solved questions on Conic Sections are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →