AP EAMCET202119 Aug 2021Morning ShiftMathematicsParabolaActual
If one end of focal chord of the parabola y 2 = 8 x is 1 2 , 2 , then the length of the focal chord is____units
Options
- A625 4
- B5 2
- C25 2
- D25
Correct answer
C. 25 2
Step-by-step solution
Given parabola is y 2 = 8 x By comparing with parabola y 2 = 4 a x a   =   2 Parametric point on parabola is a t 2 ,   2 a t   =   2 t 2 ,   4 t   =   1 2 ,   2 ⇒ 4 t   = 2 t   =   1 2 Length of focal chord will be a t + 1 t 2 =   2 1 2 + 2 2 =   2   × 25 4 = 25 2