If the length of the minor axis of an ellipse is equal to one fourth of the distance between the foci, then the eccentricity of the ellipse is :
- 3 19
- 316
- 4 17
- 57
Answer
(3) 4 17
Solution
For x2a2 + y2b2 = 1 (a > b): minor axis = 2b, distance between foci = 2ae
Given: 2b = 14(2ae) b = ae4
b2 = a2(1 - e2)
a2e216 = a2(1 - e2)
e2 = 16 - 16e2 17e2 = 16
e = 4 17
Answer: (3)