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Homework Help: Probability question - calculating marginal pdfs

  1. Dec 21, 2009 #1
    1. The problem statement, all variables and given/known data

    Calculate the marginal probability distribution function of X given joint pdf

    f(x,y) = 15x^2 y for 0 <= x <= y <= 1
    f(x,y) = 0 otherwise

    2. Relevant equations

    f_x (x) = integral of f(x,y) dy

    3. The attempt at a solution

    I've got no idea what the bounds are for this integral.

    Also, would it be easier to do it in polar coordinates?
  2. jcsd
  3. Dec 21, 2009 #2


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    Science Advisor
    Homework Helper

    0<=x<=y<=1. For a fixed value of x, doesn't y go from x to 1? I'm not sure why this is confusing you and I don't think polar coordinates will help one bit.
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