作业帮1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
来源：学生作业帮助网 编辑：作业帮 时间：2024/04/29 02:14:35
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
1/1*2*3+1/2*3*4+1/3*4*5+1/4*5*6---------+1/48*49*50
=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
1/2(1/N(N+1)-1/(N+1)(N+2))=1/N(N+1)(N+2)
然后代入1 2 3....销项即可