3道关于分数的奥数题

来源:百度知道 编辑:UC知道 时间:2024/05/07 08:39:46
(1)计算2008+20082008+200820082008/2007+20072007+200720072007
(2)计算1/1×2×3/2+1/2×3×4/2+......+1/98×99×100/2
(3) 计算(1/8+1/9+1/10+1/11)×(1/9+1/10+1/11+1/12)-(1/8+1/9+1/10+1/11+1/12)×(1\9+1\10+1\11)

急用,在线等~要计算过程和结果,不要光结果

这是后两题,第一题如果你没打错,再联系我,帮你做
2、总结规律每项可写为1/n*(n+1)*[(n+2)/2]
化简n/2+1/n+3/2即每项的通式,将n从1到98带入求和
1/2*(1+2+.....+98)+1/1+1/2+.....+1/98+3/2*98=2577.6874

3、原式=1/8×(1/9+1/10+1/11+1/12)+(1/9+1/10+1/11)×(1/9+1/10+1/11+1/12)-1/8×(1\9+1\10+1\11)+(1/9+1/10+1/11+1/12)×(1\9+1\10+1\11)
=1/8×(1/9+1/10+1/11+1/12))-1/8×(1\9+1\10+1\11)
=1/8×1/12
=1/96

(1)2008(1+10001+100010001)/2007(1+10001+100010001)=2008/2007
(2)没看明白题
(3)=1/8×(1/9+1/10+1/11+1/12)+(1/9+1/10+1/11)×(1/9+1/10+1/11+1/12)-1/8×(1\9+1\10+1\11)+(1/9+1/10+1/11+1/12)×(1\9+1\10+1\11)
=1/8×(1/9+1/10+1/11+1/12))-1/8×(1\9+1\10+1\11)
=1/8×1/12
=1/96

没看明白