Question
Class 11MathematicsConic Sections

Find the equation of the hyperbola where foci are (0,±12) and the length of the latus rectum is 36.

Verified Answer

Since foci are (0,±12), it follows that c = 12.

Length of the latus rectum =2b2/a = 36 ⇒ b2 = 18a

∴ c2 = a2 + b2

⇒ 144 = a2 + 18a

i.e., a2 + 18a - 144 = 0

So a = -24, 6

Since a cannot be negative, we take a = 6 and so, b2 = 108.

∴ The equation of the required hyperbola is y2/36 - x2/108 = 1