A.1x2
B.1x4
C.2x2
D.2x4
((X)_(1)+(X)_(2)+(X)_(3))/3 b.X1-|||-c. ((X)_(1)+(X)_(2))/2 d. (2(X)_(1)+(X)_(2)
) (x)_(1)+4(x)_(2)-2(x)_(3)+8(x)_(4)=2 -(x)_(1)+2(x)_(2)+3(x)_(3)+4(x)_(4)=1 (x)
矩阵()是二次型({x)_(1)}^2+4(x)_(1)(x)_(2)+({x)_(2)}^2的矩阵A({x)_(1)}^2+4(x)_(1)(x)_(2)+(
设x 1 2 4-|||-f(x)= 2 2 1 2-x-|||-1 2 一 x 2 4-|||-1 x x+3 x+6,证明:x 1 2 4-|||-f(x)
函数(x)=((2x-1))^4,则(x)=((2x-1))^4 (x)=((2x-1))^4函数,则
若方程组 ) 7(x)_(1)+8(x)_(2)+9(x)_(3)=0 -(x)_(2)+2(x)_(3)=0 2(x)_(2)+t(x)_(3)=0 .=
3.求解线性方程组 ) (x)_(1)+2(x)_(2)-(x)_(3)+2(x)_(4)=1 2(x)_(1)+4(x)_(2)+(x)_(3)+(x)_(
计算:(1)(5a+4c+7b)+(5c-3b-6a);(2)(8xy-x2+y2)-(x2-y2+8xy);(3)((1)/(3)(x^2)-1+3x)-4(
例4 判断二次型-|||-((x)_(1),(x)_(2),(x)_(3))=(x)_(1)^2+2(x)_(2)^2+4(x)_(3)^2+2(x)_(1)(
(B.)2y_(1)(x)-y_(2)(x)+y_(1)(x)-2y_(4)(x). (C.)2y_(1)(x)-y_(2)(x)+2y_(3)(x)-y_(