作业帮 > 数学 > 作业

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132=

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:2024/11/12 15:02:28
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132=
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132=
原式=1-1/2+1/2-1/3+1/3-1/4-1/4-1/5+1/5-1/6+.+1/11-1/12
=1-1/12
=11/12
再问: 麻烦,给详解一下
再答: 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110+1/132 =1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+...... +1/12*11 =1-1/2+1/2-1/3+1/3-1/4-1/4-1/5+1/5-1/6+......+1/11-1/12 =1-1/12 =11/12