（1x2+2x4+3x6+4x8）/（2x3+4x6+6x9+8x12)简便方法啊,

1x2+2x4+3x6+4x8 ------------------------------- 2x3+4x6+6x9+8x12简便方法啊（1x2+2x4+3x6+4x8 ）/（ 2x3+4x6+6x9+8x12） （1x2+2x4+3x6+4x8）/（2x3+4x6+6x9+8x12)简便方法啊, 1x2+2x4+3x6+4x8+5x10+.+20x40 怎么算? 1x2+2x4+3x6+4x8+5x10+.+20x40 简便计算 1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9+9x10+10x11 1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9= 数学建模的LINGO使用问题modelmin=x0+x11+x8+x9;x0+x1+x2+x3+x4+x5+x6+x7+x8+x9+x10+x11=11;x0+x1+x3+x4>=4;x1+x2+x4+x5>=4;x2+x3+x5+x6>=4;x3+x4+x6+x7>=3;x4+x5+x7+x8>=3;x5+x6+x8+x9>=4;x6+x7+x9+x10>=4;x7+x8+x10+x11>=2;x8+x9+x11+x0>=2;x9+x10+x0+x1>=1; 1x2+2x3+3x4+4x5+5x6+6x7+7x8+.+nx（n+1） 要公式,别搞太深奥! 1/1x2+1/2x3+1/3x4+.+1/n(n+1)=?1/2x4+1/4x6+1/6x8+…+1/2010x2012 2/2x4+2/4x6+2/6x8.2/8x10+2/10x2 计算题!能简算的要简算哦~(1) 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6(2)2/2x4+2/4x6+2/6x8+.+2/10x12 计算：1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8+1/8x9+1/9x10. 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7+1/7x8 算数题 求解1/1X2+1/2X3+1/3X4+1/4X5+1/5X6+1/7X8要过程 1x2+2x3+3x4+4x5+5x6+6x7+7x8+8x9+9x10+10x11+ +nx(n+1)= 2x4+4x6+6x8+.+98x100 2x3十4x6十6x9十8x12十10x15分之1x2十2x4十3x6十4x8十5x10. Min Z= X1 +X2 +X3 +X4 +X5 +X6 +X7 +X8S.T.2X1 +X2 +X3 +X4 =1002X2 +X3 + 3X5 +2X6 + X7 =100X1 + X3 + 3X4 +2X6 +3X7 +4X8 =100X1,X2,X3,X4,X5 ,X6,X7,X8 >=0经过计算的最优解是X*= (40 ,20,0,0,0 ,30 ,0 ,0)T Z* =90但该解也是最优解X*= (10 ,50,0