`x^2 - y^2 = 36`

`or, 2x - 2y(dy/dx) = 0`

`or, dy/dx = x/y`

``Now,

differentiating again we get

`2 - 2y((d^2y)/dx^2) - 2(dy/dx)^2 = 0`

`or, 2 - 2y((d^2y_/dx^2) - 2(x^2/y^2) = 0`

`or, (d^2y)/dx^2 = (y^2 - x^2)/y^3`

``

`x^2 - y^2 = 36`

`or, 2x - 2y(dy/dx) = 0`

`or, dy/dx = x/y`

``Now,

differentiating again we get

`2 - 2y((d^2y)/dx^2) - 2(dy/dx)^2 = 0`

`or, 2 - 2y((d^2y_/dx^2) - 2(x^2/y^2) = 0`

`or, (d^2y)/dx^2 = (y^2 - x^2)/y^3`

``