Q.

The length of the latus-rectum of the ellipse, whose foci are (2, 5) and (2, –3) and eccentricity is 45, is          [2025]

1 65  
2 103  
3 185  
4 503  

Ans.

(3)

We have, two foci (2, 5), (2, –3) and eccentricity =4/5

 2be=8  be=4  b(45)=4  b=5

  c2=b2a2  16=25a2  a = 3

   Length of latus rectum = 2a2b=185