1/6+1/12+1/20+1/30+……+1/9900=?
问题描述:
1/6+1/12+1/20+1/30+……+1/9900=?
答
=1/2*3+1/3*4+1/4*5+……+1/99*100
=1/2-1/3+1/3-1/4+1/4-1/5+……+1/99-1/100
=1/2-1/100
=49/100