JEE Main20209 Jan 2020Evening ShiftMathematicsParabolaActual
If one end of a focal chord A B of the parabola y 2 = 8 x is at A 1 2 , - 2 , then the equation of the tangent to it at B is:
Options
- A2 x + y - 24 = 0
- Bx - 2 y + 8 = 0
- Cx + 2 y + 8 = 0
- D2 x - y - 24 = 0
Correct answer
B. x - 2 y + 8 = 0
Step-by-step solution
Let 1 2 , - 2 is 2 t 2 , 4 t ⇒ t = - 1 2 Parameter of other end of focal chord is t = 2 ⇒ Point is 8 , 8 ⇒ Equation of tangent is 8 y - 4 x + 8 = 0 ⇒ 2 y - x = 8