【单选题】【消耗次数：1】
火焰的颜色取决于燃烧物质的化学成分和氧化剂的供应强度。大部分物质燃烧时火焰是橙红色的，但有些物质燃烧时火焰具有特殊的颜色，如（ ）燃烧的火焰是蓝色的。
①
钾
②
硫磺
③
钠
④
磷
参考答案：
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相关题目
随机题目
【单选题】
下列结论正确的是（）
①
奇异矩阵经过若干次初等变换可以化为非奇异阵
②
非奇异阵经过若干次初等变换可以化为奇异矩阵
③
非奇异等价于单位阵
④
<imgwidth="214"height="22"v:shapes="图片_x0020_120"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image127.png">
【单选题】
齐次线性方程组<imgwidth="60"height="20"v:shapes="_x0000_i1362"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image448.png">，其中<imgwidth="18"height="18"v:shapes="_x0000_i1363"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image110.png">是<imgwidth="38"height="20"v:shapes="_x0000_i1364"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image451.png">的矩阵，<imgwidth="22"height="18"v:shapes="_x0000_i1365"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image453.png">是<imgwidth="36"height="18"v:shapes="_x0000_i1366"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image455.png">的列向量则（）
①
仅有零解
②
必有非零解
③
无解
④
可能有非零解
【单选题】
<imgwidth="223"height="87"v:shapes="图片_x0020_131"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image129.png">
①
<imgwidth="219"height="34"v:shapes="图片_x0020_132"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image130.png">
②
<imgwidth="53"height="31"v:shapes="图片_x0020_133"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image131.png">
③
<imgwidth="90"height="33"v:shapes="图片_x0020_134"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image132.png">
④
<imgwidth="57"height="26"v:shapes="图片_x0020_135"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds01.files/image133.png">
【单选题】
设随机变量X服从参数<imgwidth="39"height="19"v:shapes="_x0000_i1173"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image246.png">的泊松分布，<imgwidth="36"height="21"v:shapes="_x0000_i1174"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image248.png">为X的分布函数，则下列正确的是（）
①
<imgwidth="67"height="25"v:shapes="_x0000_i1175"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image250.png">
②
<imgwidth="69"height="25"v:shapes="_x0000_i1176"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image252.png">
③
<imgwidth="144"height="27"v:shapes="_x0000_i1177"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image254.png">
④
<imgwidth="107"height="27"v:shapes="_x0000_i1178"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image256.png">
【单选题】
下列函数中可以作为某个二维随机变量的分布函数的是（）
①
<imgwidth="151"height="48"v:shapes="_x0000_i1294"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image463.png">
②
<imgwidth="152"height="48"v:shapes="_x0000_i1295"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image465.png">
③
<imgwidth="178"height="46"v:shapes="_x0000_i1296"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image467.png">
④
<imgwidth="260"height="49"v:shapes="_x0000_i1297"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image469.png">
【单选题】
已知随机变量<imgwidth="77"height="21"v:shapes="_x0000_i1134"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image174.png">，则随机变量<imgwidth="73"height="17"v:shapes="_x0000_i1135"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image176.png">的概率密度<imgwidth="54"height="25"v:shapes="_x0000_i1136"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image178.png">（）
①
<imgwidth="131"height="49"v:shapes="_x0000_i1137"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image180.png">
②
<imgwidth="123"height="49"v:shapes="_x0000_i1138"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image182.png">
③
<imgwidth="88"height="49"v:shapes="_x0000_i1139"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image184.png">
④
<imgwidth="123"height="49"v:shapes="_x0000_i1140"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb07.files/image186.png">
【单选题】
设有<imgwidth="22"height="22"v:shapes="_x0000_i1198"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image242.png">中两组基<imgwidth="70"height="26"v:shapes="_x0000_i1199"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image226.png">和<imgwidth="70"height="26"v:shapes="_x0000_i1200"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image244.png">，已知<imgwidth="206"height="28"v:shapes="_x0000_i1201"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image246.png"><imgwidth="70"height="28"v:shapes="_x0000_i1202"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image248.png">；<imgwidth="270"height="28"v:shapes="_x0000_i1203"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image250.png">，则从基<imgwidth="70"height="26"v:shapes="_x0000_i1204"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image226.png">到基<imgwidth="70"height="26"v:shapes="_x0000_i1205"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image244.png">的过渡矩阵为（）
①
<imgwidth="102"height="84"v:shapes="_x0000_i1206"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image252.png">
②
<imgwidth="102"height="84"v:shapes="_x0000_i1207"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image254.png">
③
<imgwidth="112"height="84"v:shapes="_x0000_i1208"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image256.png">
④
<imgwidth="110"height="84"v:shapes="_x0000_i1209"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds03.files/image258.png">
【单选题】
设总体<imgwidth="14"height="14"v:shapes="_x0000_i1114"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image154.png">的分布函数为<imgwidth="32"height="20"v:shapes="_x0000_i1115"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image156.png">,则总体均值<imgwidth="12"height="18"v:shapes="_x0000_i1116"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image158.png">和方差<imgwidth="18"height="20"v:shapes="_x0000_i1117"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image160.png">的矩估计分别为（）
①
<imgwidth="135"height="42"v:shapes="_x0000_i1118"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image162.png">
②
<imgwidth="173"height="40"v:shapes="_x0000_i1119"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image164.png">
③
<imgwidth="186"height="42"v:shapes="_x0000_i1120"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image166.png">
④
<imgwidth="156"height="40"v:shapes="_x0000_i1121"src="http://wljy.whut.edu.cn:80/uploadfiles/word/xxdsb11.files/image168.png">
【单选题】
<imgwidth="480"height="66"v:shapes="图片_x0020_110"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image117.png">
①
<imgwidth="62"height="26"v:shapes="图片_x0020_111"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image118.png">
②
<imgwidth="65"height="27"v:shapes="图片_x0020_112"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image119.png">
③
<imgwidth="57"height="27"v:shapes="图片_x0020_113"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image120.png">
④
<imgwidth="63"height="24"v:shapes="图片_x0020_114"src="http://wljy.whut.edu.cn/uploadfiles/word/xxds02.files/image121.png">
【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">