概率
し*** 2008-03-19 20:44:16 举报
P(B/A)=P(B/非A)=P(BA)/P(A)=P(B[非A])/P(非A) ==> P(BA)/P(A)=P(B[非A])/P(非A)= ={P(B)-P(AB)}/{1-P(A)} ==> P(BA){1-P(A)}={P(B)-P(AB)}P(A) ==> P(BA)=P(B)P(A).