1/(12)+1/(23)+1/(34)+K+1/(89)+1/(9*10)=?

题目详情

1/(1*2)+1/(2*3)+1/(3*4)+K+1/(8*9)+1/(9*10)=?

▼优质解答

答案和解析

1/﹙1×2﹚＋1/﹙2×3﹚＋1/﹙3×4﹚＋1/﹙4×5﹚＋……＋1/﹙8×9﹚＋1/﹙9×10﹚
＝1－1/2＋1/2－1/3＋1/3－1/4＋1/4－1/5＋……＋1/8＋1/9＋1/9－1/10
＝1－1/10
＝9/10.

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