Calculus

The power the differential is raised to.

The dependent variable and its derivatives are all not non-linear. \[\begin{aligned} \underbrace{\frac{d^2 y}{d t}} &\quad \underbrace{\cos(x) \frac{dy}{dx}} &\quad \underbrace{\frac{dy}{dt} \frac{d^3 y}{dt^3}} &\quad \underbrace{y’ = e^y} &\quad \underbrace{y \frac{dy}{dx}} \\ \text{linear} &\quad \text{linear} &\quad \text{non-linear} &\quad \text{non-linear} &\quad \text{non-linear} \end{aligned}\]

Independent variable does not appear in the equation.

Independent variable does appear in the equation.