KCET2007MathematicsEllipse
If the area of the auxillary circle of the ellipse x² a² + y² b² =1(a>b) is twice the area of the ellipse, then the eccentricity of the ellipse is
Options
- A1 2
- B3 2
- C1 3
- D1 2
Correct answer
B. 3 2
Step-by-step solution
Given, ellipse is x² a² + y² b² =1 , whose area is 2 a b . The auxillary circle of the ellipse is x²+y²=a² whose area is a² . Given that, a²=2 a b a=2 b Now, eccentricity of ellipse aligned &= 1- b² a² &= 1- b² 4 b² &= 4-1 4 = 3 2 aligned