P(AB)<=P(A)P(AB)<=P(B)====>P(AB)<=SQRT(P(A)P(B))P(AB)-P(A)P(B)<=SQRT(P(A)P(B))-P(A)P(B)令x=sqrt(P(A)P(B))上式=x-x^2=-(x-1/2)^2+1/4<=1/4对于负坐标轴,同理最终得到绝对值<=1/4结果
AB的是公司股份认购