问题标题：
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
问题描述：
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
陆霄晔回答：
=1/2×(1/1*2-1/2*3+1/2*3-1/3*4+1/3*4-1/4*5+……+1/48*49-1/49*50)
=1/2×(1/1*2-1/49*50)
=306/1225
点击显示
其它推荐