求和:1*2/1+2*3/1+3*4/1+······+2011*2012/1
1个回答
n*(n+1)/1 = n/1 - (n+1)/1
原式=1 -2/1 +2/1 -3/1...+2011/1 -2012/1
=1 -2012/1
=2012/2011
相关问题
1×2/1+2×3/1+3×4/1...2011×2012/1=1-2/1+2/1-3/1+.+2011/1-2012/
(-1*1/2)+(-1/2*1/3)+(-1/3*1/4)+.+(-1/2011*1/2012)+(-1/2012*1
1、(-1)+(+2)+(-3)+(+4)+•••+(-2011)+(+2012)=
(-1*1/2)+(-1/2*1/3)+(-1/3*1/4)+...+(-1/2011*1/2012)
1/1*2+1/2*3+1/3*4+...+1/2011*2012=的规律
1/1*2+1/2*3+1/3*4...+1/99*100+1/(2011*2012)
|1/2|-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|.|1/2012-1/2011|
|2/1-1|+|3/1-2/1|+4/1-3/1|+|5/1-4/1|+…+|2012/1-2011/1|=
|1/2-1|+|1/3-1/2|+|1/4-1/3|+|1/5-1/4|+…+|1/2012-1/2011|计算
已知m=1/(1+√2)+1/(√2+√3)+1/(√3+√4)+...+1/(√2011+2012),N=1-2+3-