l1签证是什么:1/2+1/6+1/12+1/20+1/30
来源:百度文库 编辑:杭州交通信息网 时间:2024/06/14 22:41:41
简算,求快,为什么
=3/6+1/6+1/12+1/20+1/30
=8/12+1/12+1/20+1/30
=15/20+1/20+1/30
=24/30+1/30
=5/6
1/2+1/6+1/12+1/20+1/30
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1-1/6
=5/6
原式=1/2+1/6+1/12+1/20+1/30
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)
=(1-1/2)+(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)=1-1/6=5/6
1/2+1/6+1/12+1/20+1/30
=(6/12+2/12+1/12)+1/30
=9/12+1/30
=45/60+2/60
=47/60
=14/30
=7/15
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?