求1/(1x2)+1/(2x3)+1/(3x4)+1/(4x5)+.+1/(2005x2006)

1/1x2+1/2x3+1/3x4+1/4x5.1/2005x2006=? 已知：X5+X4+X3+X2+X+1=0,求X2008+X2007+X2006+.+X809=? 请教一道小学数学题,1/1x2+1/2x3+1/3x4+1/4x5+.1/2005x2006怎么算?说明思路.谢谢! x6+x5+x4+x3+x2+x+1=0,求x2003+x2004+x2005+x2006+x2007+X2008=? 1/1x2+1/2X3+1/3X4+~+1/2005X2006 求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4 解方程组X2+X3+X4=1 X1+X2+X3=5 X3+X4+X5=-5 X4+X5+X1=-3 X5+X1+X2=2 X5-X4+X3+X2+X+1因式分解 x5-x4+x3-x2+x-1因式分解 已知x2+x+!=0求1+x+x2+x3+x4.+x2006的值 一道简便计算数学题1X2+2X3+3X4+4X5...+n(n+1)一1X2+2X3+3X4+4X5...+2013X2 解一道方程组x1+x2+x3=5,x2+x3+x4=1,x3+x4+x5=-5,x4+x5+x1=-3,x5+x1+x2