1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+……+(1/60+2/60+……+58/60+59/60)
问题描述:
1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+……+(1/60+2/60+……+58/60+59/60)
答
1/2+(1/3+2/3)+(1/4+2/4+3/4)+(1/5+2/5+3/5+4/5)+……+(1/60+2/60+……+58/60+59/60) =0.5+1+1.5+2……+29.5 =30*59/2 =885