For 0< < /2, if the eccentricity of the hyperbola x2-y2 cosec2 =5 is 7 times eccentricity of the ellipse x2 cosec2 +y2=5, then the value of is :
- 6
- 5 12
- 3
- 4
Answer
(3) 3
Solution
Hyperbola: x25- y25 2 =1 eH2=1+ 2
Ellipse: x25 2 + y25=1 (major axis along y-axis) eE2=1- 2
eH2=7eE2 1+ 2 =7-7 2
2 = 34 = 3
Answer: (3)