-1x1/2=-1+1/2,-1/2x1/3=-1/2+1/3,-1/3x1/4=-1/3+1/4,.发现的规律-1/n[n+1]=[ ]

问题描述:

-1x1/2=-1+1/2,-1/2x1/3=-1/2+1/3,-1/3x1/4=-1/3+1/4,.发现的规律-1/n[n+1]=[ ]

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