JEE Main 2023
Conic Sections
Ellipse
Hard
Question
Let be an ellipse. Ellipses 's are constructed such that their centres and eccentricities are same as that of , and the length of minor axis of is the length of major axis of . If is the area of the ellipse , then , is equal to _______.
Answer: 1
Solution
This problem involves a sequence of ellipses, each defined by specific geometric properties related to the previous one. We will utilize the standard formulas for ellipses, including eccentricity and area, and then identify a geometric progression to find the sum of their areas.
1. Key Concepts and Formulas for Ellipses
For an ellipse centered at the origin, with its major axis along the x-axis:
- Standard Equation: , where is the semi-major axis and is the semi-minor axis, with .
- Length of Major Axis:
- **Length