Differentiation
| D[f,x] | partial derivative  |
| D[f,x,y,...] | multiple derivative |
| D[f{x,n}] | n derivative  |
| D[f,x,NonConstants->{v1,v2,...}] | with the taken to depend on x |
Partial differentiation operations.
This gives

.
| Out[1]= |  |
This gives the third derivative.
| Out[2]= |  |
You can differentiate with respect to any expression that does not involve explicit mathematical operations.
| Out[3]= |  |
D does
partial differentiation. It assumes here that

is independent of

.
| Out[4]= |  |
| Out[5]= |  |
Instead of giving an explicit function

, you can tell
D that
implicitly depends on

.
D[y, x, NonConstants->{y}] then represents

, with

implicitly depending on

.
| Out[6]= |  |
| D[f,{{x1,x2,...}}] | the gradient of a scalar function  |
| D[f,{{x1,x2,...},2}] | the Hessian matrix for f |
| D[f,{{x1,x2,...},n}] | the n -order Taylor series coefficient |
| D[{f1,f2,...},{{x1,x2,...}}] | the Jacobian for a vector function f |
Vector derivatives.
This gives the gradient of the function

.
| Out[7]= |  |
| Out[8]= |  |
This gives the Jacobian for a vector function.
| Out[9]= |  |