1-3/2+5/6-7/12+.-19/90+21/110 .
问题描述:
1-3/2+5/6-7/12+.-19/90+21/110 .
答
1-3/2+5/6-7/12+.-19/90+21/110
=1-3/2+1/2+1/3-1/3-1/4+……-1/9-1/10+1/10+1/11
=1/11