计算:11×2
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/05 04:20:56
计算:
1 |
1×2 |
![计算:11×2](/uploads/image/z/14484557-29-7.jpg?t=%E8%AE%A1%E7%AE%97%EF%BC%9A11%C3%972)
1
1×2+
1
2×3+
1
3×4+
1
4×5+…+
1
2005×2006
=1-
1
2+
1
2-
1
3+
1
3-
1
4+
1
4-
1
5+…+
1
2005-
1
2006
=1-
1
2006
=
2005
2006
1×2+
1
2×3+
1
3×4+
1
4×5+…+
1
2005×2006
=1-
1
2+
1
2-
1
3+
1
3-
1
4+
1
4-
1
5+…+
1
2005-
1
2006
=1-
1
2006
=
2005
2006