NTA Abhyas JEE Main2020MathematicsParabolaPractice
If the normals at two points x 1 , y 1 and x 2 , y 2 of the parabola y 2 = 4 x meets again on the parabola, where x 1 + x 2 = 8 , then y 1 - y 2 is equal to
Options
- A2
- B3
- C4
- D2
Correct answer
C. 4
Step-by-step solution
Let, x 1 , y 1 ≡ t 1 2 , 2 t 1   &   x 2 , y 2 ≡ t 2 2 , 2 t 2 Now, x 1 + x 2 = 8 and both the normals again meets on the parabola, ∴   t 1 2 + t 2 2 = 8   &   t 1 t 2 = 2 On solving, we get, t 1 - t 2 2 = 4 ⇒ t 1 - t 2 = 2 ⇒ y 1 - y 2 = 4