【单选题】
实二次型<imgwidth="170"height="28"v:shapes="_x0000_i1222"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image226.png">为正定的充要条件是()
①
<imgwidth="18"height="24"v:shapes="_x0000_i1223"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image228.png">的秩为<imgwidth="14"height="16"v:shapes="_x0000_i1224"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image188.png">
②
<imgwidth="18"height="24"v:shapes="_x0000_i1225"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image228.png">的正惯性指数为<imgwidth="14"height="16"v:shapes="_x0000_i1226"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image188.png">
③
<imgwidth="18"height="24"v:shapes="_x0000_i1227"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image228.png">的正惯性指数等于<imgwidth="18"height="24"v:shapes="_x0000_i1228"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image228.png">的秩
④
<imgwidth="18"height="24"v:shapes="_x0000_i1229"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image228.png">的负惯性指数为<imgwidth="14"height="16"v:shapes="_x0000_i1230"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image188.png">
【单选题】
下列矩阵中是正定矩阵的为
①
<img title=2.png alt=2.png src=https://huaweicloudobs.ahjxjy.cn/2E080B145178AC9BC8967FE369CEE96F.png/>
②
<img title=3.png alt=3.png src=https://huaweicloudobs.ahjxjy.cn/26E3A2F475FA449B3045DA9BC7D80373.png/>
③
<img title=4.png alt=4.png src=https://huaweicloudobs.ahjxjy.cn/CBAC98B85621784032FF49E333848B11.png/>
④
<img title=5.png alt=5.png src=https://huaweicloudobs.ahjxjy.cn/D938E2337C83BB0A94D9C57BE8453611.png/>
【单选题】
下列矩阵中,不是二次型矩阵的是()
①
<imgwidth="94"height="84"v:shapes="_x0000_i1192"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image213.png">
②
<imgwidth="94"height="84"v:shapes="_x0000_i1193"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image215.png">
③
<imgwidth="106"height="84"v:shapes="_x0000_i1194"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image217.png">
④
<imgwidth="86"height="84"v:shapes="_x0000_i1195"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image219.png">