:(1-1/2-1/3-1/4-1/5)(1/2+1/3+1/4+1/5+1/6)-(1-1/2-1/3-1/4-1/5
-1/2,+1/3,-1/4,+1/5,-1/6,.
计算 ( 1+1/2)*(1-1/3)*(1+1/4)*(1-1/5)*.*(1+1/1000)*(1-1/1001)
(1+1/2)*(1+1/4)*(1+1/6)*...*(1+1/2008)*(1-1/3)*(1-1/5)*(1-1/
(1)1+1/2+1/3+1/4+1/5+1/6+1/7+1/14+1/28
1/2*1/3+1/3*1/4+1/4*1/5+1/5*1/6 (简便方法)
一道奥数题,急救!(1+1/2+1/3+1/4)×(1/2+1/3+1/4+1/5)-(1+1/2+1/3+1/4+1/
(1+2/1)(1+4/1)(1+6/1).(1+10/)(1-3/1)(1—5/1).(1-9/1)
(1-1/2)*(1-1/3)*(1-1/4)*(1-1/5)*(1-1/6)*…*(1-1/19)*(1-1/20)=
1/6【1/4{1/3(1/2X-1)+3}+5】=1
(1+1/2+1/3+1/4+1/5)*(1/3+1/4+1)-(1+1/3+1/4)*(1/2+1/3+1/4+1/5
(1) 1,1/3,1/5,1/7,1/9 (2)- 1/2*1,1/2*2,- 1/2*3,1/2*4,-1/2*5
(1/2+1/3+1/4+1/5+1/6+.+1/2013)*(1+1/2+..+1/2012)-(1+1/2+1/3+