2÷(1×3)+2÷(3×5)+2÷(5×7)+2÷(7×9)=

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/01 05:14:57

2÷(1×3)+2÷(3×5)+2÷(5×7)+2÷(7×9)=
2÷(1×3)+2÷(3×5)+2÷(5×7)+2÷(7×9)=

2÷(1×3)+2÷(3×5)+2÷(5×7)+2÷(7×9)=
=1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15
=1-1/15
=14/15