ios最终幻想9存档:1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=?
来源:百度文库 编辑:高考问答 时间:2024/07/03 08:32:02
简便算法 急求!爱 好心人.帮帮忙!!!!!
该式可转变为:
1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10=1-1/10=9/10
因为 1/2=1-1/2; 1/6=1/2-1/3; 1/12=1/3-1/4.....依此类推。
我还以为最先回答呢,等输完答案后才发现已有人捷足先登了,只好撤退了。
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/(1*2)+1/(2*3)+1/(3*4)+...+1/(9*10)
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+...+(1/9-1/10)
括号拆开,中间抵消掉
=1-1/10
=9/10
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1*1/2+1/2*1/3+1/3*1/4+...+1/8*1/9+1/9*1/10
=1-1/2+1/2-1/3+1/3-1/4+...+1/8-1/9+1/9-1/10
=1-1/10
=9/10
哈哈,简单吧!!!
分组化相同分母后再相加
如:(1/2+1/6+1/12)=6/12+2/12+1/12=9/12
1/2+1/4+1/6+......1/20=?
1+1/2-1/3+1/4-1/5+1/6+.....-1/n +1/(n+1)
1/2+1/3+1/4+1/5+1/6+1/7+.......+1/99+1/100=?
“1/1/2+2/1/6+3/1/12+4/1/12+......20/1/420”怎么简算?
(2 3/1-3 2/1+1 45/4)/(-1 6/1)
1-1/2+1/3-1/4+1/5-1/6+1/7.............-1/50=?
1-1/2-1/3-1/4-1/5-1/6-1/7-1/8-......-1/17-1/18-1/19-1/20=?
// 4,3,2,0,1,-3,( ) // 1/2,1/6,1/3,2,( ),3,1/2
1/2+1/3+1/4+1/5+1/6+1/7+...+1/n
1/2-1/3+1/4-1/5+1/6-.....-1/99+1/100的公式是什么?