1. The problem statement, all variables and given/known data The website says this: "It is Linear when the variable (and its derivatives) has no exponent or other function put on it. So no y2, y3, √y, sin(y), ln(y) etc, just plain y (or whatever the variable is). More formally a Linear Differential Equation is in the form: dy/dx + P(x)y = Q(x)" My question is whether what makes it a linear differential equation the fact that nothing on the other side of the equals sign from Q(x) has any degree higher than one or whether it is a linear differential equation because the differential doesn't have a degree higher than 1; for example, is this a linear differential equation? dy/dx + y^3 = Q(x) What about this one? dy/dx + P(x)y = Q(x)^2 2. Relevant equations 3. The attempt at a solution http://en.wikipedia.org/wiki/Linear_differential_equation http://www.mathsisfun.com/calculus/differential-equations.html Note: Sorry on the title. I meant Linear Ordinary Differential Equation. Partial should not be in there.