jacobian calculates the symbolic Jacobian \(df/dx\) of a polynomial \(f(x)\).

```
J = jacobian(f,x)
```

With only 1 argument, the differentiation is performed with respect to all involved variables (more precisely, with respect to the variables **ecover(depends(f)))**

```
x1 = sdpvar(1,1);
x2 = sdpvar(1,1);
f = x1^2+5*x2^2;
sdisplay(jacobian(f))
ans =
'2*x1' '10*x2'
```

Giving a second argument controls what variables to differentiate with respect to

```
sdisplay(jacobian(f,x2))
ans =
'10*x2'
```