Question
Represent the following family of curves by forming the corresponding differential equations (a. b: parameters).

Solution
The general equation of hyperbolas is
...(1)
Differentiating w.r.t., x successively two times, we get,

...(2)
and
...(3)
From (2), (3), we get,

which is the required differential equation.

Differentiating w.r.t., x successively two times, we get,


and

From (2), (3), we get,

which is the required differential equation.