Answer to Question #51034 in Differential Equations for Nayan Jyoti Das

Question

9. a) Find f ( y) so that equation f (y)dx − zx dy − xy ln y dz = 0 is integrable. Also obtain
the corresponding integral using Natani’s method.

b) Find the differential equation of the family of surfaces
phi [z (x + y)^2 , x^2 - y^2]=0