1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+.+1/202105

来源：学生作业帮编辑：神马作文网作业帮分类：数学作业时间：2024/11/11 13:40:50

1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+.+1/2021055
是有点难,不过还是希望大家来帮我

这个要先提取公因数2,然后再进行裂项求和即可.
1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+.+1/2021055
=2*(1/2+1/6+1/12+1/20+1/30+1/42+1/56+.1/4042110)
=2*[(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+.(2010-1/2011）
=2*[1- 1/2011 ]
=2*2010/2011
=4020/2011
1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+.+1/2021055
=1+2*(1/6+1/12+1/20+1/30+1/42+1/56+.1/4042110)
=1+2*[(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+.(1/2010-1/2011）]
=1+2*[1/2-1/2011]
=1+1-2/2011
=1又2009/2011

1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+.+1/202105 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\78+1\91+1\ 1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+1/78+1/91 【急】!简便运算!(1) 1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66 计算：1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55+1/66+q/78+1/91 1\3+1\6+1\10+1\15+1\21+1\28+1\36+1\45+1\50+1\55 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 + 1/55=? 1/3+1/8+1/10+1/15+1/21+1/28+1/36+1/45+1/55 1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/50+1/55=? 奥数数学题1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55简便运算急~ 小六计算题1+1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45+1/55=?如果把他都改成-号