1-1/2+1/3-1/4+.-1/1000+1/1001=

/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| |1-1/2|-|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| ((1/2)-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) （1+1/2)*(1+1/4)*.*(1+1/10)*(1-1/3)*(1-1/5)*.(1-1/9)简算 计算:(1-1/2)*(1-1/3)*(1-1/4)*……*(1-1/10). 1 1 1 1 1 1 1 1-1 1 1 1 1 2 3 4-1 -1 1 1 1 3 6 10-1 -1 -1 1 1 4 10 20 (1-1/2^2)*(1-1/3)*(1-1/4^2)*…*(1-1/9^2)*(1/10^2) (1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)（1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30) （1+1/1*3)*(1+1/2*4)*...*(1+1/8*10)计算 2/1 3/1 4/1 5/1 6/1 8/1 10/1 12/1 15/1 20/1 （1+2/1)×(1+3/1)×(1+4/1)×…×(1+9/1)×(1+10/1)用简算快! (1-1/2)x(1-1/3)x(1-1/4)x...x(1-1/9)x(1-1/10) 1*2/1+2*3/1+3*4/1+...+8*9/1+9*10/1简算 求和：1/1*3+1/2*4+1/3*5+.+1/n(n+1) 1/1*4+1/4*7+1/7*10+.+1/(n+2)(n+1) 1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10 1+1+2+1+2+3+1+2+3+4+.+1+2+3+...+10急