1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 16:14:57
![1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66](/uploads/image/z/134163-27-3.jpg?t=1%2F3%2B1%2F6%2B1%2F10%2B1%2F15%2B1%2F21%2B1%2F28%2B1%2F36%2B1%2F45%2B1%2F55%2B1%2F66)
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66
1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66
原式=2/(2×3)+2/(3×4)+2/(4×5)+2/(5×6)+……+2/(15×16)
=2(1/2-1/3+1/3-1/4+1/4-1/5+……+1/15-1/16)
=2×(1/2-1/16)
=7/32