向量 beta =(-1,,-|||--1,0) 可表示为α1,α2,α3的线性组合: beta =a({a)_(1)}+b(a)_(2)+(c)_(3), 则[ ].-|||-(A) a=-1 =-1 =-1 (B) =1, b=-1 =-1-|||-(C) a=-1 ,b=1, c=-1 (D) a=-1 =-1 ,c=1

8.设向量alpha_(1)=(1,0,-2)^T，alpha_(2)=(0,0,1)^T，向量beta是alpha_(1),alpha_(2)的线性组合，则下

8.若向量组α1,α2,α3线性无关, (beta )_(1)=(alpha )_(1)-(alpha )_(2), (beta )_(2)=(alpha )_

设向量0 1 2-|||-(alpha )_(1)= 1 _(2)= 1 ,beta = 1-|||--1 1 3，则0 1 2-|||-(alpha )_(1

( 1 ) 求 _(1)=((-1,2,1))^T (beta )_(2)=((1,0,b))^7的值 ; ( 2 ) 写出_(1)=((-1,2,1))^T

向量组=(1,a,c), beta =(c,1,b) ==(1,a,c), beta =(c,1,b) =，满足=(1,a,c), beta =(c,1,b)

6.设α1,α2,α3线性无关, (beta )_(1)=a(alpha )_(1)+b(alpha )_(2) (beta )_(2)=a(alpha )_(

9.设向量组α1,α 2,α3与向量组β1 β2,β3有如下关系:-|||-(beta )_(1)=(alpha )_(2)+(alpha )_(3) (bet

向量（1,2,1）和向量（1,0,c）夹角为(pi)/(3)，则c=（ ）A. $2+\sqrt{3}$B. $2\pm\sqrt{3}$C. $2-\sqrt

(2)已知beta=(1,-4,a)^T可由α_(1)=(1,2,3)^T,α_(2)=(2,1,0)^T,α_(3)=(4,-1,-6)^T线性表示，则a=_

设alpha=(3,-1,0,2)^T，beta=(3,1,-1,4)^T，若向量gamma满足2alpha+gamma=3beta，则gamma=().A.