5. For any sequence of events E1, E2,..., define a new sequence F1, F2....

of disjoint events (that is, events such that F;F; = ∅ whenever i ≠ j) such that for all n≥ 1,

$$ \bigcup_{i=1}^n F_i = \bigcup_{i=1}^n E_i $$