![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/9c16fdfaaf51f3def6e2c3fc94eef01f3b2979d1?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
(X,Y)服从一个带状区域:|x-y| ≤ 10, 0≤x,y≤60上的均匀分布,区域的面积是60²-50² = 1100
(画出图,把左上和右下三角拼起,构成一个边长为50的正方形,减去这个正方形的面积就是带状区域的面积)
Z的分布函数F(z) = P(Z ≤ z) = P(|x-y|≤z) = [60² - (60-z)²]/1100 = z(120-z)/1100, 0≤z ≤ 10.
(|x-y| ≤ z仍然表示一个带状区域,面积的算法同上)
概率密度函数为p(z) = F'(z) = (120-2z)/1100 = (60-z)/550