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