平面上建立了直角坐标系, 将每个点<img src="https://static.zxtiku.com/wangke/imgs/topic/f3ed9f47c88fc2d767c6b7e51d6e7325.jpg"/> 的坐标<img src="https://static.zxtiku.com/wangke/imgs/topic/a5591e8340b2ef5b54de82b2b20af897.jpg"/>写成列向量<img src="https://static.zxtiku.com/wangke/imgs/topic/7959aa4bb6ef2118b9629f67606dbad6.jpg"/>, <br/> <img src="https://static.zxtiku.com/wangke/imgs/topic/bae6e4ebd16f2ce455c131f1d3ab2f5f.jpg"/>. <img src="https://static.zxtiku.com/wangke/imgs/topic/3066e45adecec45cee9af1b3cb25e0db.jpg"/>是由实2阶方阵<img src="https://static.zxtiku.com/wangke/imgs/topic/a280af72788e2388cca291860a4aa21a.jpg"/>决定的变换. 如下命题哪些是正确的:<br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/695fca45e7fe242a84dd60a611ed7264.jpg"/>是正交变换,<img src="https://static.zxtiku.com/wangke/imgs/topic/a280af72788e2388cca291860a4aa21a.jpg"/>是正交方阵.<br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/695fca45e7fe242a84dd60a611ed7264.jpg"/> 是平面上绕原点 <img src="https://static.zxtiku.com/wangke/imgs/topic/8b38b7699e32d9104e36aedcea49ab91.jpg"/>的旋转.<br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/c6ec236e986227f96a27b7952128bbee.jpg"/>是特征向量, 被 <img src="https://static.zxtiku.com/wangke/imgs/topic/695fca45e7fe242a84dd60a611ed7264.jpg"/>保持不动. <br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/dedbe79b8e2b35b01e049a8709a1a2a7.jpg"/>是属于特征值 <img src="https://static.zxtiku.com/wangke/imgs/topic/dea140272a65b70eb6186f8bcb681e0e.jpg"/> 的特征向量.<br/> E、<img src="https://static.zxtiku.com/wangke/imgs/topic/695fca45e7fe242a84dd60a611ed7264.jpg"/>是平面上关于直线 <img src="https://static.zxtiku.com/wangke/imgs/topic/dba4ff1b9a2db3ad9ef4b1a873e9ca58.jpg"/>的轴对称, <img src="https://static.zxtiku.com/wangke/imgs/topic/f3ed9f47c88fc2d767c6b7e51d6e7325.jpg"/>的坐标为<img src="https://static.zxtiku.com/wangke/imgs/topic/1e1e009af861a81c66c4264ec1b598b0.jpg"/>.