Notes for AKT-090924-2/0:39:41

Hints:

1. Leibniz rule for derivative of products:

[math]\displaystyle{ \partial_x(f.g)=(\partial_x f) g +f (\partial_x g) }[/math]

2. Iterated Leibniz rule (for expressions like [math]\displaystyle{ (\partial_x \partial_y \partial_z) (f.g) }[/math])

3. Leibniz rule in a discrete (combinatorial) setting:

[math]\displaystyle{ (f.g)(\doublepoint)=f(\doublepoint)g(\overcrossing) + f(\undercrossing)g(\doublepoint) }[/math]