【单选题】【消耗次数：1】
龈沟深度的正常值为（）
①
0.5～2mm
②
0.5～3mm
③
1mm
④
3.5mm
⑤
以上都不是
参考答案：
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相关题目
【单选题】
塑料排水带的宽度为100mm，厚度为5mm，则其当量换算直径（换算系数取1.0）为（）。
①
25.2mm；
②
66.8mm；
③
33.4mm；
④
50.4mm；
随机题目
【单选题】
若<imgwidth="80"height="21"v:shapes="_x0000_i1198"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image288.png">都存在，则下面命题中错误的是（）
①
<imgwidth="247"height="21"v:shapes="_x0000_i1199"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image290.png">
②
<imgwidth="215"height="21"v:shapes="_x0000_i1200"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image292.png">
③
<imgwidth="152"height="21"v:shapes="_x0000_i1201"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image294.png">
④
<imgwidth="163"height="21"v:shapes="_x0000_i1202"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image296.png">
【单选题】
设A，B表任意二随机事件，则下面错误的是（）
①
<imgwidth="16"height="17"v:shapes="_x0000_i1102"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image152.png">与<imgwidth="16"height="20"v:shapes="_x0000_i1103"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image154.png">互不相容
②
<imgwidth="110"height="21"v:shapes="_x0000_i1104"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image156.png">
③
<imgwidth="27"height="20"v:shapes="_x0000_i1105"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image158.png">表示<imgwidth="16"height="17"v:shapes="_x0000_i1106"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image152.png">与<imgwidth="16"height="17"v:shapes="_x0000_i1107"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image161.png">都不发生
④
若<imgwidth="80"height="21"v:shapes="_x0000_i1108"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image163.png">，则<imgwidth="239"height="25"v:shapes="_x0000_i1109"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb06.files/image165.png">
【单选题】
<imgwidth="44"height="16"v:shapes="_x0000_i1068"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image062.png">矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1069"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的秩为<imgwidth="18"height="16"v:shapes="_x0000_i1070"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">，则（）
①
<imgwidth="18"height="18"v:shapes="_x0000_i1071"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意一个<imgwidth="18"height="16"v:shapes="_x0000_i1072"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">阶子式都不等于零
②
<imgwidth="18"height="18"v:shapes="_x0000_i1073"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意一个<imgwidth="42"height="20"v:shapes="_x0000_i1074"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image068.png">阶子式都不等于零
③
<imgwidth="18"height="18"v:shapes="_x0000_i1075"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的任意<imgwidth="18"height="16"v:shapes="_x0000_i1076"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">个列向量必线性无关
④
对于任一<imgwidth="18"height="16"v:shapes="_x0000_i1077"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">维列向量<imgwidth="14"height="20"v:shapes="_x0000_i1078"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image070.png">，矩阵<imgwidth="56"height="28"v:shapes="_x0000_i1079"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image072.png">的秩都为<imgwidth="18"height="16"v:shapes="_x0000_i1080"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image065.png">
【单选题】
<imgwidth="183"height="25"v:shapes="_x0000_i1194"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image285.png">，且<imgwidth="21"height="25"v:shapes="_x0000_i1195"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image287.png">与<imgwidth="22"height="25"v:shapes="_x0000_i1196"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image289.png">相互独立，则<imgwidth="68"height="25"v:shapes="_x0000_i1197"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image291.png">（）
①
<imgwidth="84"height="25"v:shapes="_x0000_i1198"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image293.png">
②
<imgwidth="92"height="25"v:shapes="_x0000_i1199"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image295.png">
③
<imgwidth="88"height="41"v:shapes="_x0000_i1200"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image297.png">
④
<imgwidth="96"height="41"v:shapes="_x0000_i1201"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image299.png">
【单选题】
设<imgwidth="14"height="16"v:shapes="_x0000_i1089"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image004.png">元齐次线性方程组<imgwidth="54"height="20"v:shapes="_x0000_i1090"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image030.png">的通解为<imgwidth="108"height="32"v:shapes="_x0000_i1091"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image083.png">则矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1092"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的秩（）
①
<imgwidth="62"height="24"v:shapes="_x0000_i1093"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image086.png">
②
<imgwidth="90"height="24"v:shapes="_x0000_i1094"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image088.png">
③
<imgwidth="66"height="24"v:shapes="_x0000_i1095"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image079.png">
④
<imgwidth="18"height="18"v:shapes="_x0000_i1096"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds04.files/image008.png">的每行元素之和都不等于零
【单选题】
以下结论中不正确的是（）
①
若存在可逆矩阵<imgwidth="18"height="20"v:shapes="_x0000_i1238"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image243.png">，使<imgwidth="70"height="24"v:shapes="_x0000_i1239"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image245.png">，则<imgwidth="18"height="18"v:shapes="_x0000_i1240"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image246.png">是正定矩阵
②
二次型<imgwidth="158"height="28"v:shapes="_x0000_i1241"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image248.png">是正定二次型
③
<imgwidth="14"height="16"v:shapes="_x0000_i1242"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image249.png">元实二次型正定的充分必要条件是<imgwidth="18"height="24"v:shapes="_x0000_i1243"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image233.png">的正惯性指数为<imgwidth="14"height="16"v:shapes="_x0000_i1244"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image249.png">
④
<imgwidth="14"height="16"v:shapes="_x0000_i1245"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image249.png">阶实对称矩阵<imgwidth="18"height="18"v:shapes="_x0000_i1246"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image246.png">正定的充分必要条件是<imgwidth="18"height="18"v:shapes="_x0000_i1247"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image246.png">的特征值全为正数
【单选题】
某人打靶的命中率为0.8，现独立地射击5次，那么5次中有2次命中的概率为（）
①
<imgwidth="75"height="25"v:shapes="_x0000_i1078"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image105.png">
②
<imgwidth="41"height="25"v:shapes="_x0000_i1079"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image107.png">
③
<imgwidth="96"height="26"v:shapes="_x0000_i1080"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image109.png">
④
<imgwidth="96"height="26"v:shapes="_x0000_i1081"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image111.png">
【单选题】
下列各式中有（）等于<imgwidth="120"height="28"v:shapes="_x0000_i1263"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image281.png">
①
<imgwidth="146"height="58"v:shapes="_x0000_i1264"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image283.png">
②
<imgwidth="146"height="58"v:shapes="_x0000_i1265"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image285.png">
③
<imgwidth="166"height="58"v:shapes="_x0000_i1266"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image287.png">
④
<imgwidth="156"height="58"v:shapes="_x0000_i1267"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds05.files/image289.png">
【单选题】
设随机变量<imgwidth="19"height="17"v:shapes="_x0000_i1111"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image123.png">的数学期望<imgwidth="68"height="21"v:shapes="_x0000_i1112"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image145.png">，方差<imgwidth="75"height="25"v:shapes="_x0000_i1113"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image147.png">，则由切比雪夫不等式有<imgwidth="118"height="21"v:shapes="_x0000_i1114"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image149.png">（）
①
<imgwidth="16"height="41"v:shapes="_x0000_i1115"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image151.png">
②
<imgwidth="16"height="41"v:shapes="_x0000_i1116"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image153.png">
③
<imgwidth="16"height="41"v:shapes="_x0000_i1117"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image130.png">
④
<imgwidth="15"height="41"v:shapes="_x0000_i1118"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb09.files/image132.png">
【单选题】
设<imgwidth="70"height="26"v:shapes="_x0000_i1082"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image096.png">是方程组<imgwidth="60"height="20"v:shapes="_x0000_i1083"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image098.png">的基础解系，则下列向量组中也可作为<imgwidth="60"height="20"v:shapes="_x0000_i1084"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image098.png">的基础解系的是（）
①
<imgwidth="174"height="26"v:shapes="_x0000_i1085"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image100.png">
②
<imgwidth="222"height="26"v:shapes="_x0000_i1086"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image102.png">
③
<imgwidth="138"height="26"v:shapes="_x0000_i1087"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image104.png">
④
<imgwidth="140"height="26"v:shapes="_x0000_i1088"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image106.png">