1+1/3+1/6+1/10+.+1/4950
问题描述:
1+1/3+1/6+1/10+.+1/4950
答
1+1/3+1/6+1/10+.+1/4950
=2×(1/2+1/6+1/12+1/20+……+1/9900)
=2×(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+……+1/99-1/100)
=2×(1-1/100)
=2×99/100
=99/50
=1.98