設(shè)A是m×n矩陣,B是n×m矩陣,則( ?。?br/>A. 當(dāng)m>n時(shí),必有行列式|AB|≠0
B. 當(dāng)m>n時(shí),必有行列式|AB|=0
C. 當(dāng)n>m時(shí),必有行列式|AB|≠0
D. 當(dāng)n>m時(shí),必有行列式|AB|=0
∵AB為m階方陣,且秩r(AB)≤min[r(A),r(B)]≤min(m,n),
∴當(dāng)m>n時(shí),有:r(AB)≤n<m,
即:AB不是滿秩的,故有行列式:
=0,
故選:B.