1/2×4+1/4×6+1/6×8+1/8×10+1/10×12 = = = 每一步都要

如题所述

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相关建议 2012-06-16

原式=1/2×（1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10+1/10-1/12）
=1/2×（1/2-1/12）
=1/2×5/12
=5/24

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第1个回答 2012-10-27

1/2*4+1/4*6+1/6*8+…+1/2010*2012
=1/2（1/2-1/4+1/4-1/6+1/6-1/8+……+1/2010-1/2012）
=1/2*（1/2-1/2012）
=1005/4024

第2个回答 2012-06-16

原式=2+1+2/4+1+2/6+1+2/8+1+2/10
=5+(1+1/2+1/3+1/4+1/5)

1\/2X4+1\/4X6+1\/6X8+1\/8X10+1\/10X12=
1\/2X4+1\/4X6+1\/6X8+1\/8X10+1\/10X12==(1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+1\/8-1\/10+1\/10-1\/12)÷2 =（1\/2-1\/12）÷2=5\/12÷2=5\/24 1-5\/6+7\/12-9\/20+11\/30 =1\/6+7\/12-9\/20+11\/30 =(1\/2-1\/3)+(1\/3+1\/4)-(1\/4+1\/5)+(1\/5+1\/6)=1\/2+1\/6 ...

1\/2*4+1\/4*6+1\/6*8+...+1\/2010*2012 简便方法
1\/4*6=(1\/2)*(1\/4-1\/6)。。。所以：1\/2*4+1\/4*6+1\/6*8+...+1\/2010*2012 =(1\/2)*(1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+。。。+1\/2010-1\/2012)=(1\/2)*(1\/2-1\/2012)=(1\/2)*(1005\/2012)=1005\/4024 无量寿佛，佛说苦海无涯回头是岸!施主，我看你骨骼清奇，器宇轩...

1\/2×4+1\/3×5+1\/4×6+1\/5×7+……+1\/8×10+1\/9×11 数学题
所以原式=（1\/2-1\/4+1\/3-1\/5+1\/4-1\/6+...+1\/9-1\/11)\/2 =(1\/2+1\/3-1\/10-1\/11)\/2 =53\/165

计算,1\/2x4+1\/4x6+1\/6x8+...+1\/48x50=?,1\/2+1\/6+1\/12+1\/20+1\/30+1\/...
计算，1\/2x4+1\/4x6+1\/6x8+...+1\/48x50 =1\/2×（1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+……+1\/48-1\/50）=1\/2×（1\/2-1\/50）=1\/2×12\/25 =6\/25，1\/2+1\/6+1\/12+1\/20+1\/30+1\/42 =1-1\/2+1\/2-1\/3+1\/3-1\/4+1\/4-1\/5+1\/5-1\/6+1\/6-1\/7 =1-1\/7 =6...

1\/2*4+1\/4*6\/+1\/6*8+1\/8*10……+1\/198*200=?这道题的思路是什么
每一项都裂项即1\/2*4=（1\/2-1\/4）\/2 1\/4*6=（1\/4-1\/6）\/2 ……则原式=（1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+……+1\/198-1\/200）\/2 =（1\/2-1\/200）\/2 =99\/400

求解奥数1\/2*4+1\/4*6+1\/6*8+1\/8*10+...+1\/98*100详细步骤多谢啦
1\/2*4+1\/4*6+1\/6*8+1\/8*10+...+1\/98*100 =（1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+1\/8-1\/10+……+1\/98-1\/100）\/2 =（1\/2-1\/100）\/2 =49\/200

1\/2*4+1\/4*6+1\/6*8+1\/8*10+1\/10*12+1\/12*14
1\/2*4+1\/4*6+1\/6*8+1\/8*10+1\/10*12+1\/12*14＝1\/8×（1+1\/3+1\/6+1\/10+1\/15+1\/21)=

1\/2*4+1\/4*6+1\/6*8+1\/8*10+1\/10*12+1\/12*14
1\/2*4+1\/4*6+1\/6*8+1\/8*10+1\/10*12+1\/12*14 =(1\/2)(2\/2*4+2\/4*6+2\/6*8+2\/8*10+2\/10*12+2\/12*14)=(1\/2)(1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+1\/8-1\/10+1\/10-1\/12+1\/12-1\/14)=(1\/2)(1\/2-1\/14)=3\/14 ...

1\/2*4+1\/4*6+1\/6*8+1\/8*10+1\/10*12+1\/12*14
=1\/4（1\/1*2+1\/2*3+1\/3*4+1\/4*5+...）=1\/4(1-1\/2+1\/2-1\/3+1\/3-1\/4...)=1\/4*(1-1\/7)=1\/4*6\/7 =3\/14

1\/2×4+1\/4×6+1\/6×8+…1\/16×18+1\/18×20简便运算
1\/2×4+1\/4×6+1\/6×8+……+1\/18×20 =(1\/2)×(1\/2-1\/4+1\/4-1\/6+1\/6-1\/8+...+1\/18-1\/20）=(1\/2)×(1\/2-1\/20)=(1\/2)×9\/20 =9\/40 请记得采纳哟谢谢！