hessian calculates the Hessian \(d^2^f/dx^2\) of a polynomial expression

```
H = hessian(f,x)
```

With only 1 argument, the differentiation is performed with respect to all involved variables

```
x1 = sdpvar(1,1);
x2 = sdpvar(1,1);
f = x1^4+5*x2^2;
sdisplay(hessian(f))
ans =
'12*x1^2' '0'
'0' '10'
```

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

```
sdisplay(hessian(f,x1))
ans =
'12x1^2'
```