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Homework Help: Joint density

  1. May 2, 2013 #1
    1. The problem statement, all variables and given/known data
    Let the joint density of the material and labor cost of a project be modeled by
    fx,y(u,v) = 2v*e-v*(2+u) u,v ≥ 0
    = 0 otherwise

    a) find marginal density of X and Y
    b) find E(Y)

    2. Relevant equations
    Marginal density of Y should be ∫fx,y(u,v) du from 0 to ∞, unless there is some other relationship between X and Y, and u and v that I am missing. I get undefined when trying to do this integral, so I know it can't be right.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. May 2, 2013 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Show your work; the integration gives a simple, finite answer, so you must be doing something wrong.
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