NTA Abhyas JEE Main2020MathematicsParabolaPractice
The length of the chord of the parabola x 2 = 4 y having equation x - 2 y + 4 2 = 0 is
Options
- A6 3 units
- B8 2 units
- C2 11 units
- D3 2 units
Correct answer
A. 6 3 units
Step-by-step solution
Solving the equations of the given parabola and the line, we get, 2 y - 4 2 2 = 4 y ⇒ y 2 - 10 y + 16 = 0 ⇒ y 1 - y 2 = y 1 + y 2 2 - 4 y 1 y 2 = 100 - 64 = 6 ⇒ Length of the chord = A B = x 1 - x 2 2 + y 1 - y 2 2 = 2 y 1 - y 2 2 + y 1 - y 2 2 = 3 y 1 - y 2 = 6 3