1+1+1+1/5+8/4+9/2

1+1+1+1/5+8/4+9/2 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) 化简:1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9+1/9*10 1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10 5+1+2+1+3+9+8+4+5 1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9+1/10等于多少? 用放缩法 求证1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9 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的答案是多少? 数列计算 1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9=?数列计算 1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9=?1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9+1/10=?最主要的是怎么计算的过程。 数列计算 1/2+1/3+1/4+1/5+1/6+1/7+1/8+1/9=? 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=?希望把过程写出来 1/2 × 1/5 +1/3 ×1/6+1/4×1/7+1/5×1/8+1/6×1/9+1/7×1/10 3+1+5+6+9 1+8+2+0+3 4+1+8+3+9 1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=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=1-1/9=8/9为什么呢?写出解析. 1/2×4+1/3×5+1/4×6+1/5×7+……+1/8×10+1/9×11 (-1-1/2)*(-1-1/3)*(-1-1/4)*(-1-1/5)*(-1-1/6)*……*(-1-1/9)*(-1-1/10)(-1-1/2)*(-1-1/3)*(-1-1/4)*(-1-1/5)*(-1-1/6)*（-1-1/7）*（-1-1/8）*(-1-1/9)*(-1-1/10) - - - - - - - - - 》《- - 7 1- -2 8 -》《8 9- -5 3 - - 1》《- -4 - - - - - 9》《- 5 - 3 - 8 - 2 -》《1 - - - - - 4 - -》《5 - - 7 2 - - 4 3》《 - 3 1 - - 6 9 - -》《- - - - - - - - -》