NTA Abhyas JEE Main2020MathematicsParabolaPractice
The locus of the middle points of the chords of the parabola y 2 = 4 a x , which passes through the origin is
Options
- Ay 2 = a x
- By 2 = 2 a x
- Cy 2 = 4 a x
- Dx 2 = 4 a y
Correct answer
B. y 2 = 2 a x
Step-by-step solution
Let mid point be ( x 1 , y 1 ) ∴ Equation of chord is T = S 1 y y 1 - 2 a x + x 1 = y 1 2 - 4 a x 1 Since, it passes through origin ∴ - 2 a x 1 = y 1 2 - 4 a x 1 ⇒ y 1 2 = 2 a x 1 ∴ Locus is y 2 = 2 a x