1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/23 15:01:45
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?1/2+1/6+1/12+1/20+1/30

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=?
1/2+1/6+1/20+1/30+1/42+1/56+1/72
=1/1 ×2+1/2×3+1/3×4……+1/8×9
=(2-1)/1 ×2+(3-2)/2×3+(4-3)/3×4……+(9-8)/8×9
=1-1/2+1/2-1/3+1/3-1/4+……+1/8-1/9
=1-1/9
=8/9