北京东城中医医院招聘:1/10+1/40+...+1/340=? 3/20+3/30+...+3/9900=?

来源：百度文库编辑：神马品牌网时间：2024/05/03 06:28:19

写出过程

解:1/10+1/40+...+1/340
=1/2*5+1/5*8+1/8*11+...+1/17*20
=(1/3)(1/2-1/5+1/5-1/8+1/8-1/11+...+1/17-1/20)
=(1/3)(1/2-1/20)
=3/20
2.3/20+3/30+...+3/9900
=3(1/20+1/30+...+1/9900)
=3(1/4*5+1/5*6+1/6*7+...+1/99*100)
=3(1/4-1/5+1/5-1/6+...+1/99-1/100)
=3(1/4-1/100)
=3(96/400)
=288/400
=18/25

1/10+1/40+...+1/340=? 3/20+3/30+...+3/9900=? 齐齐算 1/(10/1+12/1) 1/6+1/8+1/10+1/12+..........+1/202=? 一:1／8＝1/( )+1/( )二:1/10=1/( )+1/( )三:1/12=1/( )+1/( )+1/( ) 1+1/1+2+1/1+2+3+......+1/1+2+3+......+10 1/6+1/24+1/60+1/40= -1/10-1/11-1/11-1/12-…-1/19-1/20 (1-1/2^2)(1-1/3^2)....(1-1/10^2) (1-1/2^2)(1-1/3^2)....(1-1/10^2) 1/4+1/12+1/24+1/40+……+1/19800=?