Equation of the family of curves 
……….(i)
Differentiating both sides two times w.r.t. 
……….(ii)
Again differentiating w.r.t. ,
……….(iii)
Putting this value of 
in eq. (ii), we get
Form a differential equation representing the given family of curves by eliminating arbitrary constants a and b in \[{{\mathbf{y}}^{\mathbf{2}}}~=\text{ }\mathbf{a}\text{ }({{\mathbf{b}}^{\mathbf{2}}}~-\text{ }{{\mathbf{x}}^{\mathbf{2}}})\]
Form a differential equation representing the given family of curves by eliminating arbitrary constants a and b in \[{{\mathbf{y}}^{\mathbf{2}}}~=\text{ }\mathbf{a}\text{ }({{\mathbf{b}}^{\mathbf{2}}}~-\text{ }{{\mathbf{x}}^{\mathbf{2}}})\]