神马作文网分数的巧算,求详细过程
来源：学生作业帮 编辑：神马作文网作业帮 分类：数学作业 时间：2024/11/16 01:05:14
分数的巧算,求详细过程
=(15+1)/3×5+(35+1)/5×7+(63+1)/7×9+(99+1)/9×11+(143+1)/11×13+(175+1)/13×15
=1+1/3×5+1+1/5×7+1+1/7×9+1+1/9×11+1+1/11×13+1+1/1315
=6+1/3×5+1/5×7+1/7×9+1/9×11+1/11×13+1/13×15
=6+1/2(2/3×5+2/5×7+2/7×9+2/9×11+2/11×13+2/13×15)
=6+1/2(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15)
=6+1/2(1/3-1/15)
=6+2/15
=6又2/15
=1+1/3×5+1+1/5×7+1+1/7×9+1+1/9×11+1+1/11×13+1+1/1315
=6+1/3×5+1/5×7+1/7×9+1/9×11+1/11×13+1/13×15
=6+1/2(2/3×5+2/5×7+2/7×9+2/9×11+2/11×13+2/13×15)
=6+1/2(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15)
=6+1/2(1/3-1/15)
=6+2/15
=6又2/15