$$\sum_{k=0}^{n-1}2^{k}=2^n-2$$
$$x\in\Sigma_{bool}$$
$$\sum_{k=0}^{n-8}2^k$$
$$F \land (G \lor H) \equiv (F \land G) \lor (F \land H)$$
$$1. \tex B \lor (A \land \neg A) \ B \lor \bot$$

basically what I would do here is to just take the definition of divergence for a vector field F: $$div F = sum of dF_i/dx_i$$ and apply that for $$F = grad f =\Delta f =(df/dx_1, …, df/dx_n)$$