若A为正交矩阵,则( )<br>·<img src="/lqwvjeImg/f8/f84203d408268751fedcc62d42aeac4f.png"style="width:52px;height:26px;"><br>·<img src="/lqwvjeImg/5e/5eb74df798742274b13dfb8932bc4757.png"style="width:16px;height:16px;">能对角化<br>·<img src="/lqwvjeImg/5e/5eb74df798742274b13dfb8932bc4757.png"style="width:16px;height:16px;">为对称矩阵<br>·以上都不对.