Find the equation of the hyperbola whose foci are (0, ±10) and the length of whose latus rectum is 9 units.

Given: Foci are (0, ±10) and the length of latus rectum is 9 units


Need to find: The equation of the hyperbola.


Let, the equation of the hyperbola be:


The length of the latus rectum is 9 units.


Therefore, ---- (1)


The foci are given at (0, ±10)



That means, ae = 10, where e is the eccentricity.


We know that,


Therefore,




[Squaring both sides]


[From (1)]





So, either a = 16 or, a =


That means, either b = or, b =


The value of b = is not a valid one. So, the b value and its corresponding a value is not acceptable.


Hence, the acceptable value of a is 16 and b is


So, the equation of the hyperbola is,


[Answer]


1