1/(12×13)+1/(13×14)+……+1/(19×20)的值为:

恬恬2019-12-17  15

问题 1/(12×13)+1/(13×14)+……+1/(19×20)的值为:A1/12B1/20C1/30D1/40

选项

答案C

解析[img]/upload/tiku/284/2960038_1.png[/img]
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