1*2/1+2*3/1+3*4/1+.98*99/1+99*100/1=?

|1-1/2|-|1/2-1/3|-|1/3-1/4|-.-|1/9-1/10| |1-1/2|+|1/2-1/3|+|1/3-1/4|+...|1/9-1/10| 1:8 2:9 1:9 3:4 1:3 ... /1/3-1/2/+/1/4-1/3/+/1/5-1/4/+.+/1/10-1/9/ |1/3-1/2|+|1/4-1/3|+|1/5-1/4|+...+|1/10-1/9| 1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1简算 有理数:-1/2+1/3-(-1/9)-1/4= 1/1*3+1/2*4+...+1/9*11=? 1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10 (1-1/2^2)*(1-1/3)*(1-1/4^2)*…*(1-1/9^2)*(1/10^2) （1+1/2)*(1+1/4)*.*(1+1/10)*(1-1/3)*(1-1/5)*.(1-1/9)简算 1×2/1+1×2+2×3/1+…+1×2+2×3+3×4+…9×10/1 1+2+3+.9 lim(1+1/3+1/9+...+1/3^(n1))/(1+1/2+1/4+...+1/2^(n-1)) lim(1+1/3+1/9+...+1/3^(n1))/(1+1/2+1/4+...+1/2^(n-1))急 |3/1-2/1|+|4/1-3/1|+|5/1-4/1|+...+|10/1-9/1|=?3Q 9*(1-1/2)*(1-1/3)*(1-1/4)*(1-1/5)*(1-1/6)*(1-1/7)*(1-1/8)*(1-1/9)怎样简便计算 ((1/2)-1)*((1/3)-1)*((1/4)-1)*((1/5)-1)*((1/6)-1)*((1/7)-1)*((1/8)-1)*((1/9)-1)*((1/10)-1)