概率论题目若X～U(3,5)，Y～E(2)则E(2Y+3)＝？D(-3X+2)＝？
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|X~5261N(3.5)
E(X)=3, D(X)=5
Y~e(2)
E(Y) = (1/2)(4+2) = 3
E(Y^41022) = (1/2) ∫(2->4) y^2 dy = (1/6)[ y^3 ] |(2->4) = 56/6 = 28/3
D(Y) = E(Y^2) -[E(Y)]^2 = 28/3 -9 = 1/3
E（X+Y）1653=E(X)+E(Y) = 1+3 =4
D(-3x+2) = D(X) + D(Y) = 9 + 1/3 = 28/3
咨询记录 · 回答于2021-08-15
概率论题目若X～U(3,5)，Y～E(2)则E(2Y+3)＝？D(-3X+2)＝？
|X~5261N(3.5)E(X)=3, D(X)=5Y~e(2)E(Y) = (1/2)(4+2) = 3E(Y^41022) = (1/2) ∫(2->4) y^2 dy = (1/6)[ y^3 ] |(2->4) = 56/6 = 28/3D(Y) = E(Y^2) -[E(Y)]^2 = 28/3 -9 = 1/3E（X+Y）1653=E(X)+E(Y) = 1+3 =4D(-3x+2) = D(X) + D(Y) = 9 + 1/3 = 28/3
5261是什么？你的输入法是不是搞错了？
嗯对，你把前面的忽略一下，撤回不了
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