ABC三个事件,证明P(AUBUC).令D=AUB,P(AUBUC)=P(DUC)=P(D)+P(C)-P(DC),-------------(1)P(D)=P(A)+P(B)-P(AB),---------------------------------(2)P(DC)=P(ACUBC)=P(AC)+P(BC)-P(ABC).-------------------(3)(2)和(3)代入(1)即可.
