UC知道一道简便运算题(急~~~~~~）
来源：百度知道 编辑：UC知道 时间：2024/05/14 12:10:06
-1/2+1/6+1/12+1/20＋1/30+1/42
=0-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=0-1/7
=-1/7
-1/2+1/6+1/12+1/20＋1/30+1/42
=-1/7
-1/2+1/4+1/12+1/42
=-1/6+1/42
=-1/7
-1/7
原式=-1/2+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)
=-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=-1/7
1/2+1/6+1/12+1/20＋1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
所以原式=1-1/7=6/7
这个答案保证对 请采纳我 谢谢!!!!