JEE Main 2023
Conic Sections
Parabola
Hard
Question
The focus of the parabola is the centre of the circle of radius 5 . If the values of , for which C passes through the point of intersection of the lines and , are and , then is equal to ________ .
Answer: 2
Solution
This problem is a comprehensive test of analytical geometry, requiring a strong grasp of parabolas, circles, and straight lines. The solution involves a sequence of steps: first, identifying the key properties of the parabola to find the center of the circle; second, defining the circle's equation; third, finding the intersection point of two lines in terms of a parameter ; and finally, using the condition that this point lies on the circle to solve for .
1. Key Concepts and Formulas
- Parabola: The standard form of a parabola opening to the right with its vertex at the origin is . Its focus is at . If the parabola is shifted, its equation becomes $(y-k)^2 =