问题标题:
(1+½)*(1-½)*(1+1/3)*(1-1/3)*.*(1+1/99)*(1-1/99)简便计算
问题描述:
(1+½)*(1-½)*(1+1/3)*(1-1/3)*.*(1+1/99)*(1-1/99)简便计算
陈祥光回答:
(1+1/n)(1-1/n)=(n-1)(n+1)/n^2
所以
(1+1/2)(1-1/2)...(1+1/99)(1-1/99)=(1*3)/(2*2)*(2*4)/(3*3)*...*(98*100)/(99*99)=1/2*100/99=50/99
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