In the Ordinary Differential Equation, the derivatives of the dependent variable with respect to only one independent variable are used. Ordinary differential equations have the form F(x, y, y',..., yn-1) = yn. In a partial differential equation, there are derivatives for more than one variable that acts on its own. The formula for the partial differential equation is ∂u/∂x (x,y) = 0 The order of a differential equation is set by the derivative of the dependent variable with respect to the independent variable that has the highest order. A first-order linear differential equation has the form dy/dx +Py Q, where P and Q are constants or functions of just x. The term "solution" refers to a function that satisfies a particular differential equation.