简算:1/1+2+1/1+2+3+1/1+2+3+4+…+1/1+2+3+4+…+41
简算:1/(1*2) + 1/(2*3) + 1/(3*4) + 1/(4*5) + 1/(5*6) + …… + 1/
1/(1-1/2)/(1-1/3)/(1-1/4)/……/(1-1/2012)
| 1/3 - 1/2 | + | 1/4 - 1/3 | + | 1/5 - 1/4 | …… + | 1/2009
(-1*2/1)+(-1/2*1/3)+(-1/3*1/4)+…+(-1/2012*1/2013)
计算:(1-1/2)*(1-1/3)*(1-1/4)*……*(1-1/10).
200×(1-1/2)×(1-1/3)×(1-1/4)×……×(1-1/100)=?
求和:1/1×2+1/2×3+1/3×4+……+1/n(n+1)
1/2*1+1*2*3+1/3*4+………+1/99*100
(1/3+1/4……+1/2006)(1/2+1/3……+1/2006)-(1/2+1/3+……+1/2006)(1/3
1-1*(1+2)分之2-(1+2)*(1+2+3)分之3-(1+2+3)*(1+2+3+4)分之4-……-(1+2+…
计算:(1+1/2)(1+1/3)(1+1/4)…(1+1/2010)(1/2-1)(1/3-1)(1/4-1)…(1/
计算(1-1/2^2)(1-1/3^2)(1-1/4^2)……(1-1/50^2)