谁知道1x1+2x2+3x3+4x4+99x99有没有公式求和?
求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4
1/1x2+1/2x3+1/3x4+1/4x5+.+1/98x99+1/99x100
1/1X2+1/2x3+1/3x4+1/4x5+.+1/98x99+1/99x100求结果!
2/1x2+2/2x3+2/3x4+2/4x5+...+2/98x99+2/99x100
求1x2,2x3,3x4,4x5,……98x99,99x100的倒数和
求非齐次线性方程组:2x1-x2+4x3-3x4=-4;x1+x3-x4=-3;3x1+x2+x3=1;7x1+7x3-
1x1!+2x2!+3x3!+4x4!.nxn!
求线性方程组 x2-x3-x4=0 x1+x2-x3+3x4=1 x1-x2+x3+5x4=-1 x1+2x2-2x3+
a为何值时,线性方程组{x2+x3-2x4=1、2x1+5x2+5x3-4x4=3、x1+3x2+3x3+3x4=a有解
当b为何值时,线性方程组X1+X2+X3+X4=1,3X1+2X2-X3-X4=0,X2+4X3+4X4=b有解,有解求
1x1 2x2 3x3 4x4 5x5```````nxn有什么规律
用列主元Gauss消元法解线性方程组{-x2-x3+x4=0,x1-x2+x3-3x4=1,2x1-2x2-4x3+6x