Mathematica 教程

# Derivatives of Unknown Functions

Differentiating a known function gives an explicit result.
 Out[1]=
Differentiating an unknown function f gives a result in terms of f'.
 Out[2]=
Mathematica applies the chain rule for differentiation, and leaves the result in terms of f'.
 Out[3]=
Differentiating again gives a result in terms of f, f' and f''.
 Out[4]=
When a function has more than one argument, superscripts are used to indicate how many times each argument is being differentiated.
 Out[5]=
This represents . Mathematica assumes that the order in which derivatives are taken with respect to different variables is irrelevant.
 Out[6]=
You can find the value of the derivative when x=0 by replacing x with 0.
 Out[7]=
 f '[x] first derivative of a function of one variable f(n)[x] nth derivative of a function of one variable f (n1, n2, ... )[x] derivative of a function of several variables, ni times with respect to variable i

Output forms for derivatives of unknown functions.