(a1+a2,a2+a3,a3+a1) = (a1,a2,a3)KK=1 0 11 1 00 1 1因为 |K|=2≠0,所以K可逆所以 r(a1+a2,a2+a3,a3+a1) = r(a1,a2,a3)所以 a1+a2,a2+a3,a3+a1 线性无关 r(a1+a2,a2+a3,a3+a1) = 3 r(a1,a2,a3) = 3 a1,a2,a3 线性无关