what is an exact derivative?

Question

I don't mean exact differential, the book I was reading referred specifically to an exact derivative.

Answer 1

An derivative is nothing more then the rate of change in a quantity. It gives us the instantaneous rate of change at a point. . An exact derivative, by definition, would be a solution that is not approximated [an exact answer].

Answer 2

i've heard of it as exact differential form hope that helps. you can probably look it up on wikipedia for the definition. its usually associated with vector fields