1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算

来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 05:09:31
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算
xP 0 (r] "X[  %>[9;K%ט–agy']ߤ%¯Xd-a{礗<2scju᝾x 5qq Gqk}\?

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90简算
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1-1/10
=9/10

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1-1/2+1/2-1/3+1/3-1/4+……+1/8-1/9+1/9-1/10
=1-1/10
=9/10

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1-1/10
=9/10