1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)1 1 1 1 1___+___+___+___+……+___=?1x2 2x3 3x4 4x5 39x40
来源：学生作业帮助网 编辑：六六作业网 时间：2024/11/26 06:33:50
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)11111___+___+___+___+……+___=?1x22x33x44x539x401/1*2+1
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)1 1 1 1 1___+___+___+___+……+___=?1x2 2x3 3x4 4x5 39x40
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)
1 1 1 1 1
___+___+___+___+……+___=?
1x2 2x3 3x4 4x5 39x40
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40=?(化简!)1 1 1 1 1___+___+___+___+……+___=?1x2 2x3 3x4 4x5 39x40
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40
=(1-1/2)+(1/2-1/3)+.+(1/39-1/40)
=1-1/40
=39/40
1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+...1/39*40
=(1-1/2)+(1/2-1/3)+....+(1/39-1/40)
=1-1/40
=39/40