矩阵的行列式为
|a1 a2 a3|
=(λ+3)(1-λ)(λ+3)+(3λ+3)+2λ^2-2(3λ+3)(1-λ)-λ(λ+3)-λ(λ+3)
= -λ^3+λ^2-6λ+6
= -(λ-1)(λ^2+6) ,
所以 λ=1 时,向量组线性相关 .