｛2X1-X2+3X3=33X1+X2-5X3=04X1-X2+X3=3X1+3X2-13X3=-6{X1-2X2+3X3-4X4=4X2-X3+X4=-3X1+3X2-3X4=1-7X2+3X3+X4=-3

求解线性方程组 X1+X2+X3=6 2X1+3X2+X3=11 X1-X2+2X3=5 max Z=2X1+4X2-5X3 X1+X2+X3=7 2X1-3X2+X3≥10 X1.X2.X3≥0 ｛2X1-X2+3X3=33X1+X2-5X3=04X1-X2+X3=3X1+3X2-13X3=-6{X1-2X2+3X3-4X4=4X2-X3+X4=-3X1+3X2-3X4=1-7X2+3X3+X4=-3 x1+5x2-x3-x4=-1x1-2x2+x3+3x4=33x1+8x2-x3+x4=1 消元法解线性代数4X1+2X2-X3=23X1-X2+2X3=1011X1+3X2 =8 线性代数里的r(x1,x2,x3,x1+2x2)=r(x1,x2,x3)?为什么? 线性方程组{2x1-x2-2x3=λx1{5x1-3x2-3x3=λx2{-x1+2x3=-λx3有非零解,则λ= 解线性方程组 x1-x2-x3=2 x1+x2+4x3=0 3x1+5x3=3 求解非齐次线性方程组x1+x2+x3=3,x2-x3=0,-x1-x2+2x3=0,2x1-x2+x3=2 解方程组 X1-X2-4X3=-1 X2+X3=2 X1+X2-2X3=3线性代数 用初等行变换来解下列线性方程组（1）2x1-x2+3x3=3 3x1+x2-5x3=0 4x1-x2+x3=3 x1+3x2-13x3=-6(2) x1-2x2+x3+x4=1 x1-2x2+x3-x4=-1 x1-2x2+x3-5x4=5(3) x1-x2+x3-x4=1 x1-x2-x3+x4=0 x1-x2-2x3+2x4=-1/2 mathematica如何求解含有三角函数的方程?FindRoot[{3 x1^3 + 2 x2 - 5 + Sin[x1 - x2] Sin[x1 + x2] == 0,-x1*Exp[x1 - x2] + x2 (4 + 3 x2^2) + 2 x3 + Sin[x2 - x3] Sin[x2 + x3] - 8 == 0,-x2*Exp[x2 - x3] + 4 x3 - 3 ==0},{x1,Pi/2},{x2,2},{x3,0}] 二次型f(x1,x2,x3)=(x1)^2+3(x2) ^2-4(x3)^2+6(x1)(x2)+10(x2)(x3)的矩阵是 设X1,X2,X2是方程X3+PX+q=0的3个根,计算行列式 X1 X2 X3 X3 X1 X2 X2 X3 X1 求解齐次线性方程组X1+2X2-4X4=-3X1-X2-4X3+9X4=222X1-3X2+X3+5X4=-33X1-2X2-5X3+X4=3 若点(x1,1),(x2,2),(x3,-3)都是反比例函数y=-1/x图象上的点,则( ) A.x1>x2>x3 B.x1>x3>x2C.x3>x2>x1 D.x3>x1>x2 试用克拉默法则求下列线性方程组的解 x1+x3=1;2x1+2x2+3x3=3;x2+x3=-1x1+x3=12x1+2x2+3x3=3x2+x3=-1 已知x1>0,x2>0,x3>0;求证x1^2/x2+x2^2/x3+x3^2/x1>=x1+x2+x3