来自姜传广的问题
1,2,3,4……100.一百个数中任取三个数构成等差数列的概率
1,2,3,4……100.一百个数中任取三个数构成等差数列的概率
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2020-03-02 09:36
1,2,3,4……100.一百个数中任取三个数构成等差数列的概率
1,2,3,4……100.一百个数中任取三个数构成等差数列的概率
100个数中取3个数共有100*99*98/(3*2*1)=1617设取得的等差数列公差为d当d=1时,有100-2=98种取法当d=2时,有2*(50-2)=96种取法·········································...