[NumCS] Add more sympy tricks

semester3/numcs/parts/06_python/03_sympy.tex

@@ -4,3 +4,6 @@ Sympy can be used to do symbolic operations, i.e. similar to what we would do in
 
 You usually want to follow something like the below code:
 \inputcode{python}{parts/06_python/03_sympy-ex.py}
+
+It is also possible to compute the hessian and gradient using sympy (or also the jacobian):
+\inputcode{python}{parts/06_python/03_sympy-hessian.py}