设x1>=x2>=x3>=x4>=2,x2+x3+x4>=x1,求证:(x1+x2+x3+x4)^2
1个回答
令x1=k(x2+x3+x4)
1/3(x2+x3+x4)
相关问题
x1+5x2+2x3-4x4=3 -3x1-2x2+3x3+4x4=-6 -x1+3x2-x3-4x4=-2 -2x1+
求方程组X1-3X2-2X3-X4=1 3X1-8X2-4X3-X4=0 -2X1+X2-4X3+2X4=1 -X1-2
求线性方程组x1-3x2-2x3-x4=1,3x1-8x2-4x3-x4,-2x1+x2-4x3+2x4=1,-x1-2
(x1-x2+4x3-2x4=0;x1-x2-x3+2x4=0;3x1+x2+7x3-2x4=0;x1-3x2-12x3
1x2=1/3(1x2x3=0x1x2 ) 2x3=1/3(2x3x4-1x2x3) 3x4=1/3(3x4x5- 2x
线性方程组为:x1-x2-5x3+4x4=2 2x1-x2+3x3-x4=1 3x1-2x2-2x3+3x4=3 7x1
1x2=1|3(1x2x3-0x1x2) 2x3=1|3(2x3x4-1x2x3) 3x4=1|3(3x4x5-2x3x
求非.X1+X2-X3+X4=1 ,X1-X2+X3-3X4=1,X1-X2-2X3+3X4=-1/2
X1+2X2-X3+X4=12X1-3X2+X3+2X4=23X1-X2+3X4=3X1-5X2+2X3+X4=1还是打
解线性方程组(1)2x1-x2+x3-2x4=7 (2)x1+2x2-3x3=-4 (3)-x1-x2+x3+4x4=4