<span style、"font-family: 'times new roman', times, serif;">若<em>A,B</em>均为<em>n</em>阶对称矩阵，则<em>AB</em>也是对称矩阵</span>
<span style、"font-family: 'times new roman', times, serif;">若<em>A,B</em>均为<em>n</em>阶非零矩阵，则<em>AB</em>也是非零矩阵</span>
<span>对任意方阵<span style、"font-family: 'times new roman', times, serif;"><em>A</em></span></span><span style="font-family: 'times new roman', times, serif;"><em>，A+A'</em></span><span>是对称矩阵</span>
<span>若<span style、"font-family: 'times new roman', times, serif;"><em>A,B</em></span></span><span>均为<span style="font-family: 'times new roman', times, serif;"><em>n</em></span></span><span>阶非零矩阵，则<img src="http://oss.ouchn.cn/zongbu/jiaoyu/工程数学（本）/xingkao1/1191.png" alt=""></span>