So I have recently begun my first graduate level engineering math class. The course teaches us different techniques for solving various differential equations. Many of these equations I have never actually seen being applied to something, they are only just examples for us to learn how to solve them. So I am curious what kind of physical systems these equations model. For example: Bernoulli Differential Equations Ricatti Equation Euler-Cauchy Equations Many of the other equations are just first order equation that are unlike any Ive seen be applied to something in my courses before. Such as... x (x^2+y^2) dy/dx = y^3 dy/dx = (x+y) / (x-y) There are many more but I wont bother putting too many specific examples. Thanks in advance, and I look forward to reading your responses.