a1=(1,2,3,4)a2=(2,3,4,5)a3=(3,4,5,6)a4=(4,5,6,7)a1,a2 是线性无关2a2-a1=(3,4,5,6)=a32a3-a2=(4,5,6,7)=a4所以a1,a2,a3,a4 的秩=2
