The term "total derivative" has several related meanings in mathematics. It is used as an alternate term for the convective derivative.
It also denotes the derivative along a curve of a function depending on both a parameter
and intermediate variables. Let , where
and the
are differentiable. The
chain rule gives
where the partial derivatives of are evaluated at
. The partial
derivative
holds the
fixed, whereas
includes their dependence on
(Lebl 2026, pp. 38-41).
More generally, the total derivative of a function of several real variables denotes its Fréchet derivative, the linear transformation giving its first-order approximation. Its matrix in the standard bases is the Jacobian (Lebl 2026, pp. 35-40).
The total derivative of a function with respect to
is implemented in the Wolfram
Language as Dt[f[t,
x, y, ...], t].