 In what follows, let "y" be a dependent variable and "x" an independent variable, and "y" = "f"("x") is an unknown function of "x".The notation for differentiation varies depending upon the author and upon which notation is most useful for the task at hand.In this context, the Leibniz's notation ("dy"/"dx","d"2"y"/"dx"2...,"d""n""y"/"dx""n") is more useful for differentiation and integration, whereas Lagrange's notation ("y′","y′′", ..., "y"("n")) is more useful for representing derivatives of any order compactly, and Newton's notation formula_3 is often used in physics for representing derivatives of low order with respect to time.