随机变量<imgwidth="13"height="21"v:shapes="_x0000_i1042"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image036.png">的概率密度<imgwidth="132"height="50"v:shapes="_x0000_i1043"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image038.png">则常数<imgwidth="29"height="19"v:shapes="_x0000_i1044"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image040.png">()
③
<imgwidth="17"height="41"v:shapes="_x0000_i1045"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image042.png">
④
<imgwidth="17"height="41"v:shapes="_x0000_i1046"src="http://wljy.whut.edu.cn/uploadfiles/word/xxdsb08.files/image044.png">