56.5x6.5+44.5x4.5+44.5x2简算

1x2+2x4+3x6+4x8+5x10+.+20x40 怎么算? 1x2+2x4+3x6+4x8+5x10+.+20x40 简便计算 1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101 逐差法求加速度公式为什么要用a=（x6+x5+x4-x3-x2-x1）/9t平方 而不用a=x6-x1/5t平方 (2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==? 1/1X2+1/2X3+1/3X4+1/4X5+1/5X6……1/2007X2008 1x2/1+2x3/1+3x4/1+4x5/1+5x6/1+6x7/1 当x分别等于3和-3时，多项式6x2+5x4-x6+3的值是（　　） 求编程高手.求x1+2*x2+3*x3+4*x4+5*x5+9*x6的最小值 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+......1/2008x2009 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7 用秦九韶算法计算当X=3时多项式f(x)=7X7+6x6+5x5+4x4+3X3+2x2+X的值