A hyperbola has its centre at the origin, passes through the point ( 4,2 ) and has transverse axis of length 4 along the x -axis. Then the eccentricity of the hyperbola is:
(A)32✓ Correct
(B)23
(C)3
(D)2
Answer: (A)
Solution
Take the hyperbola as a2x2−b2y2=1 with transverse axis 2a=4, so a=2 and a2=4. It passes through (4,2): 416−b24=1, so 4−b24=1 and b2=34. The eccentricity is e=1+a2b2=1+44/3=34=32.
JEE Main · 2019 · 09 Jan 2019 · Shift 2 · Single correct option