Differential equations are those types of equations that have some derivatives of certain functions. The derivatives can either be ordinary derivatives or partial derivatives. If there are only ordinary derivatives in the equation then, the equation is defined as the ordinary type of differential equation and if the equation has all its terms as partial derivative then, such type of equation is called as partial differential equation.
In mathematics, a partial derivative of a function of several variables is its derivative with respect to one of those variables, with the others held constant (as opposed to the total derivative, in which all variables are allowed to vary). Partial derivatives are used in vector calculus and differential geometry. #Glogster #PartialDerivatives
In mathematics, the directional derivative of a multivariate differentiable function along a given vector v at a given point x intuitively represents the instantaneous rate of change of the function, moving through x with a velocity specified by v. It therefore generalizes the notion of a partial derivative, in which the rate of change is taken along one of the coordinate curves, all other coordinates being constant. #Glogster #DirectionalDerivatives
Partial derivatives are so called because they're the derivatives of multivariable functions. When a function is defined in terms of two or more variables, the function's derivative is actually a collection of partial derivative equations.