=(1/2)*[1/2+1/6+1/12+1/20+...+1/9900]
=(1/2)*[1/1*2+1/2*3+1/3*4+1/4*5+...+1/99*100]
=(1/2)*[1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100]
=(1/2)*[1-1/100]
=(1/2)*(99/100)
=99/200
求采纳
=(1/2)*[1/2+1/6+1/12+1/20+...+1/9900]
=(1/2)*[1/1*2+1/2*3+1/3*4+1/4*5+...+1/99*100]
=(1/2)*[1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100]
=(1/2)*[1-1/100]
=(1/2)*(99/100)
=99/200
=1/2-1/200
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1\/4+1\/12+1\/24+1\/40+……+1\/19800 求详细解题过程!!!
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如何巧算1\/4+1\/12+1\/24+1\/40+.+1\/19800
1\/4+1\/12+1\/24+1\/40+.+1\/19800 =1\/2(1-1\/2+1\/2-1\/3+1\/3-1\/4+……+1\/99-1\/100)=1\/2（1-1\/100）=99\/200
如何巧算1\/4+1\/12+1\/24+1\/40+...+1\/19800
1\/4+1\/12+1\/24+1\/40+...+1\/19800 =1\/2(1-1\/2+1\/2-1\/3+1\/3-1\/4+……+1\/99-1\/100)=1\/2（1-1\/100）=99\/200 ljt86836祝你学习进步!
1\/4+1\/12+1\/24+1\/40……+1\/19800 算式和结果都要写上,
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1\/2-1\/4)\/2+(1\/3-1\/5)\/2+(1\/4-1\/6)\/2+……+（1\/97-1\/99）\/2+(1\/98-1\/100)\/2 =(1-1\/3+1\/2-1\/4+1\/3-1\/5+1\/4-1\/6+...+1\/97-1\/99+1\/98-1\/100)\/2 =（1+1\/2-1\/99-1\/100）\/2 =（3\/2+199\/9900）\/2 =(14651\/9900)\/2 =14651\/19800 ...
好记星的50层魔塔的真魔王打不动啊!
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把(1\/1)*2+(1\/2)*3+...+(1\/99
1\/1*2+1\/2*3+1\/3*4···+1\/99*100简便算，！要算式思路 1\/1*2+1\/2*3+1\/3*4···+1\/99*100 =1\/(1×2)+1\/(2×3)+...+1\/(99×100) =(1-1\/2)+(1\/2-1\/3)+...+(1\/99-1\/100) =1-1\/2+1\/2-1\/3+...+1\/99-1\/100 =1-1\/100 =99\/100 ...
