Let the foci of a hyperbola be (1,14) and (1,−12). If it passes through the point (1,6), then the length of its latus-rectum is :
(A)625
(B)524
(C)5288✓ Correct
(D)5144
Answer: (C)
Solution
The foci (1,14) and (1,−12) lie on the vertical line x=1, and the center is their midpoint, (1,1).
Distance between foci =2c=14−(−12)=26, so c=13.
Since the hyperbola passes through (1,6), which also lies on x=1 (the transverse axis), this point is a vertex. Distance from center (1,1) to (1,6) is a=5.
Then b2=c2−a2=169−25=144.
For a hyperbola with vertical transverse axis, a2(y−k)2−b2(x−h)2=1, the length of the latus rectum is ℓ=a2b2:
ℓ=52×144=5288.
JEE Main · 2025 · 22 Jan 2025 · Shift 1 · Single correct option