【概率论】作业四

151220129 吴政亿 已知X~g(p)和Y~g(q) P(X=Y)=∑∞i=0((1−p)(1−q))ipq=pqp+q−pq P(min(X,Y)=k)=P(X=k,Y=k)+P(X=k,Y>k)+P(X>k,Y=k) =(1−p)k−1(1−q)k−1pq+(1−p)k−1p∑∞i=k((1−q)iq)+(1−q)k−1q∑∞i=k((1−p)ip) =(1−p)k−1(1−q)k−1p

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