Leibniz notation writes the derivative of a function 
as 
. The symbols 
and 
are called differentials.
For a function of several variables, partial derivatives are written using the partial derivative symbol, for example 
.
Higher derivatives are written
 |
where the exponent on 
records the order of differentiation. Although 
resembles a quotient and can be manipulated like one in
many formulas, it denotes the derivative as a whole unless the differentials have
separately been defined in a setting such as differential
geometry.
