1/6=1/2X3=1/2-1/3,1/12=1/3X4=1/3-1/4,1/20=1/4X5=1/4-1/5, (1)
解方程组X2+X3+X4=1 X1+X2+X3=5 X3+X4+X5=-5 X4+X5+X1=-3 X5+X1+X2=2
求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4
求解一个方程急 X(1次方)+X2+X3=5 X2+X3+X4=1 X3+X4+X5=-5 X4+X5+X1=-3 X5
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
1分解因式:2x4-x3-13x2-15=?2.分解因式:x5+x4+x3+x2+x+1=?3分解因式:x4-4x2+6
1/1x2+1/2x3+1/3x4+1/4x5+```````+1/2008x2009=?
1/1x2+1/2x3+1/3x4+1/4x5.1/2005x2006=?
式子如下:1 1 1 1 1--- + --- + --- + --- + .+ ---- = 2x3 3x4 4x5
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
1/1x2+1/2x3+1/3x4+1/4x5+.+1/2007x2008=多少 怎么计算
一定要帮我啊!(1/1x2)+(1/2x3)+(1/3x4)+(1/4x5)+.+(1/99x100)=?
已知一组数据x1,x2,x3,x4,x5的方差S^2=1/5(x1^2+x2^2+x3^2+x4^2+x5^2-45),