设A为n阶方阵，E为n阶单位矩阵，且A2=A，则（A-2E）-1=____.

n阶方阵A具有n个不同的特征值是A与对角阵相似的______．

设A、B均为n阶方阵，A有n个互异的特征值，且AB＝BA，证明：B相似于对角矩阵。

设A、B均为n阶方阵，A有n个互异的特征值，且AB=BA，证明:B相似于对角矩阵.

设A是n阶方阵，n≥3．已知|A|=0，则下列命题正确的是（）．

设A为n阶方阵，则n元齐次线性方程组AX=0仅有零解的充要条件是|A|____.

设A为n阶方阵，则n元齐次线性方程组AX(→)＝0(→)仅有零解的充要条件是|A|____。

A declaration made by the Master before a PRC Consul，giving particulars regarding heavy weather or other incidents which may have caused damage to the vessel or cargo，through no fault of the vessel，her officers，or crew is a(n)（）.

A vessel or object being towed astern shall display a(n)（）.

The movement of water away from the shore or downstream is called a(n)（）.

A current moving across a lock entrance toward the river or toward the dam is called a(n)（）.

A为n阶方阵，若存在n阶方阵B，使AB=BA=A，则_________。