A differential equation is an equation that relates a function to its derivatives, which represent the rate of change of that function. The function could be dependent on one or more variables, and the derivatives indicate how the function changes with respect to those variables.
Key Terms:
- Function: The quantity that is changing, typically denoted as y(x)y(x) y ( x ) or f(x)f(x) f ( x ) , where xx x is the independent variable.
- Derivative: Represents the rate of change of the function. For example, dydx\frac{dy}{dx} dxdy denotes the rate of change of yy y with respect to xx x .
- Order: The order of a differential equation is the highest derivative in the equation. For example, if the equation involves d2ydx2\frac{d^2y}{dx^2} dx 2 d 2 y , it is a second-order differential equation.
- Degree: The degree of a differential equation is the power of the highest-order derivative. For example, d2ydx2+y=0\frac{d^2y}{dx^2} + y = 0 dx 2 d 2 y + y = 0 is a second-degree equation.