线生成真题汇总
本题考查行列式的性质:两行(列)相加后的行列式等于行列式相加,一行(列)k次的行列式等于k次的行列式。
|A+B|=|α+β,(1+λ)γ1,(1+μ)γ2|=|α,(1+λ)γ1,(1+μ)γ2|+|β,(1+λ)γ1,(1+μ)γ2|
=(1+λ)(1+μ)|α,γ1,γ2|+(1+λ)(1+μ)|β,γ1,γ2|=(1+λ)(1+μ)(a+b)
|A+B|=|α+β,(1+λ)γ1,(1+μ)γ2|=|α,(1+λ)γ1,(1+μ)γ2|+|β,(1+λ)γ1,(1+μ)γ2|
=(1+λ)(1+μ)|α,γ1,γ2|+(1+λ)(1+μ)|β,γ1,γ2|=(1+λ)(1+μ)(a+b)