The question is incomplete. Here is the complete question.
A differential equation is given along with the field of problem area which it arises. Classify it as an ordinary differential equation (ODE) or a partial different equation (PDE), give the order, and indicate the independent and dependent variables. If the equation is an ordinary differential equation, indicate whether the equation is linear or nonlinear.
[tex]x\frac{d^{2}y }{dx^{2} } + \frac{dy}{dx} + xy = 0[/tex] (aerodynamics, stress analysis)
Answer and Step-by-step explanation: The differential equation described above is an Ordinary Differential Equation, because it has a definite set of variables: x and y.
It is of Second Order, since the highest derivative is of order 2: [tex]\frac{d^{2}y }{dx^{2} }[/tex]
The differential equation is written as derivative of a function y in terms of x, which means: Independent Variable is X and Dependent Variable is Y.
As it is an ODE, the equation is Nonlinear, because y'' or [tex]\frac{d^{2}y }{dx^{2} }[/tex] is multiplied by a variable.