作业帮1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/20 09:26:19
xQ
0l>rHIAy@(&O@i'l,HDHΎGr5dvO,p/͏J5? ηn쏄%b=';'&"v!pbnMzBx/Yj^E*0W%F3w`c3δJ VCA9n Xz&K:-s:J-ޤWKi/MY;D@Ax(Mu9t] d#
1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80
1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80
1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80
嗯,原式=2（1/8+1/24+1/48+1/80）+2（1/15+1/35+1/63）+1/3
=2[1/（2*4）+1/（4*6）+1/（6*8）+1/（8*10)]+2[1/(3*5)+1/(5*7)+1/(7*9)]+1/3
=[1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10]+[1/3-1/5+1/5-1/7+1/7-1/9]+1/3
=1/2-1/10+1/3-1/9+1/3
=(1/2-1/10)+(1/3-1/9+1/3)
=(5-1)/10+(3-1+3)/9=2/5+5/9=(18+25)/45=43/45