JEE Main 2024
Conic Sections
Parabola
Hard
Question
Let a conic pass through the point and , be any point on . Let the slope of the line touching the conic only at a single point be half the slope of the line joining the points and . If the focal distance of the point on is , then equals ________.
Answer: 5
Solution
This problem requires us to identify a conic section from a given geometric property, determine its specific equation using a point it passes through, and finally calculate a focal distance. The journey involves setting up and solving a differential equation, recognizing the standard form of a conic, and applying its properties.
1. Problem Analysis and Initial Setup
We are given the following information about a conic :
- It passes through the point .
- For any point on (with ), there's a specific relationship between the slope of the tangent line at and the slope of the line joining to a fixed point . *