[機統] 雙變數函數求期望值
8
f(x,y)=---xy if 0<x<1 x<y<2x
3
1 2x 8
求E(XY)=S S --- x^2 y^2 dydx= 56/54 (詳解)
0 x 3
2 y 8
=S S --- x^2 y^2 dxdy = 56/54 (我自已算的)
0 y/2 3
問題出在:
1 2x 8
E(X)=S S --- x^2 y dydx=4/5 (詳解)
0 x 3
2 y 8
E(X)=S S --- x^2 y dxdy=224/45 (自已算的)-------->(*)
0 y/2 3
範圍我有積錯的話應該E(XY)也會錯= = 為什麼E(X)不能讓我這樣算
我漏了什麼 跪求
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 1.174.45.176
※ 文章網址: http://www.ptt.cc/bbs/Math/M.1397476072.A.86A.html
→
04/14 20:44, , 1F
04/14 20:44, 1F
→
04/14 20:46, , 2F
04/14 20:46, 2F
→
04/14 20:46, , 3F
04/14 20:46, 3F
推
04/15 07:41, , 4F
04/15 07:41, 4F
討論串 (同標題文章)